Previously I always thought it was just tactical and technique, but every match has become almost mental and physical—I try to push myself to move well. I try to push myself not to get upset and stay positive, and that's what my biggest improvement is over all those years. Under pressure I can see things very clear.
Post match press conference after winning Dubai Open 2007.
All four of those are on grass, whereas I have to play some on a hard court!
Humorously explaining why it is more difficult for him to win all four grand slams in Tennis than it is for Tiger Woods to win in Golf.
It's just unreal, I'm shocked myself. I've played good matches here, but never really almost destroyed somebody.
After defeating Andy Roddick in the Australian Open 2007 semi-final.
It was just one of those days for him to forget and me to remember.
After defeating Andy Roddick in the Australian Open 2007 semi-final.
No no no, too late! Stop! Yeah, come on… I was allowed to challenge for like two seconds, the guy takes like ten… Every time! I can't allowed that stuff to happen! You have any rules in there or what ?! Stop showing me your hand, ok?! Don't tell me to be quite, ok?! When I wanna talk, I talk, allright?! I don't give a shit what he said, I just say he's waiting way too long…
Criticising umpire during 2009 US Open heatbreaking final against Juan Martin del Potro, who took long before challenging a wide call. Scene on Youtube
Sometimes you're just happy playing. Some people, some media, unfortunately, don't understand that it's okay just to play tennis and enjoy it. They always think you have to win everything, it always needs to be a success story, and if it's not, obviously, what is the point? Maybe you have to go back and think, Why have I started playing tennis? Because I just like it. It's actually sort of a dream hobby that became somewhat of a job. Some people just don't get that, ever.
I think you need inspiration, motivation from different angles to keep you going, because it isn’t that simple just to wake up every morning and go for another travel around the world, another practice, all these other things; another fitness workout, another stretch. It’s always nice, but you need to have some success and you need to have the right reasons why you’re doing it. I think I’ve always been able to do that and I really enjoy myself out on the court.
No, the other one was a night session too and I was wearing a white! No I'm not supersticious at all as you can see and… I try not to be… and because I try no to be, I guess I am… So it's really strange!
After defeating Joe-Wilfried Tsonga, quarter final of Australian Open 2013, when asked by Jim Courrier if he was wearing a black tee-shirt for a night session as a supersticious man. Interview on Youtube
Andy Murray shouted to his coaching team, after running out of idea against Federer at Wimbledon 2015 
He hits shots that other guys don’t hit. You want to go over and give him a high five sometimes, but you can’t do that. You want to beat him but he’s fun to watch, too.
Sam Querrey was in awe after Federer flashed his racquet between his legs to lob him at Wimbledon 2015 
Because he can cover so well to the forehand, it really allows him to stay at home in the backhand corner. That backhand corner gets smaller and smaller, sort of dares you to hit the forehand. There's a lot of times you do, and you're thinking that it's a good idea, then a second later you're going, 'Why did I do that?'
[Federer] ...is the most beautiful man to watch play tennis. The most beautiful I've ever seen play. His movement, combined with the artistry, his racquet, the look, he's got everything going.
John McEnroe, winner of 7 Grand Slams, while commentating on United State's Tennis Channel on June 1, 2012 
We are witnessing history. This is the most dominant athlete on planet earth today.
Jim Courier, former world No.1, while commentating on Australia's Channel Seven in 2007
For me Roger is the greatest player ever who played the tennis game. It’s always good to see him play and win and we are going to see so much more of Federer in the future; he is going to win more grand slam tournaments.
Bjorn Borg, winner of 11 Grand Slams, after Federer won the 2009 French Open Final
It’s a combination of how many grand slams have you won, how many tournaments have you won, how many years you were number one, and he’s got all those combinations. The body of work is phenomenal and now he has got that French Open and I think he can just go on and sip Margaritas for the rest of his life.
What he’s done over the past five years has never, ever been done — and probably will never, ever happen again. Regardless if he won there or not, he goes down as the greatest ever. This just confirms it. Now that he has won in Paris, I think it just more solidifies his place in history as the greatest player that played the game, in my opinion. I’m a huge Laver fan, and he had a few years in there where he didn’t have an opportunity to win majors. But you can’t compare the eras. And in this era, the competition is much more fierce than Rod’s.
Pete Sampras, winner of 14 Grand Slams, after Federer winning 2009 French Open Final
His win today at the French Open, tying Pete Sampras’s record for major titles and the completion of a career grand slam firmly places him in a special place as the greatest player of all time. He has earned his place and he has proven he belongs. Roger is a champion for the ages.
Roger Federer will undoubtedly become the greatest tennis player to have graced the sport if he wins the French Open. It ends the discussion of where he fits in the history of the game. If it wasn't for [four-time champion Rafael] Nadal, he probably would have won a handful of these things. So nobody would underestimate where he deserves to fit in this game. He's extraordinarily talented and talk about grace on court; watching him play is something special to see and if he does it tomorrow, he'll know what an accomplishment it was.
You guys are brutal. Absolutely brutal. The guy has only made two Grand Slam finals this year. I would love his bad year. I would love it.
Andy Roddick, to the press, on what he made of press' criticism for Federer's dip in form in 2008 that saw him slip to No. 2 in the world; US Open 2008- Day 7 quotes 
For me, in my prime, I felt unbeatable. In Roger's days, he's unbeatable. It's really hard to put one guy over the other. Having said that, I think Roger is dominating the game much more than I ever did. I think he's going to go on and pass 14 and win 16, 17, 18 majors. I think he's going to break all records.
Pete Sampras, before playing his third exhibition match with Roger Federer, Macau, China, Nov. 23, 2007.
I had a taste of what the best is tonight and I think Roger has that extra gear. He has good volleys and he has this little backhand flick that honestly, I have never seen before... it’s something that I didn’t have. I am happy with my performance tonight. I hung in there right until the end.
Pete Sampras, after playing his second exhibition match with Roger Federer, Kuala Lumpur, Nov. 22, 2007.
If he is playing very good, I have to play unbelievable. If not, it’s impossible, especially if he’s playing with good confidence. When he’s 100 percent, he’s playing in another league. It’s impossible to stop him. I fight. I fight. I fight. Nothing to say. Just congratulate him.
Rafael Nadal, after losing to Federer in the Shanghai Masters Cup semifinal, Nov. 17, 2007. 
In my opinion he's the best player ever. When you play tennis, playing Federer is kind of a dream because you can see he does everything you would love to do on the court.
He's the most gifted player that I've ever seen in my life. I've seen a lot of people play. I've seen the (Rod) Lavers; I played against some of the great players—the Samprases, Beckers, Connors', Borgs, you name it. This guy could be the greatest of all time. That, to me, says it all.
Roger is just the greatest player of all time. He is the most beautiful player I’ve ever seen and I don’t ever get tired of watching him. Rod Laver is my idol, Pete Sampras is the greatest grass court player ever, but Roger is just the greatest player of all. I think we can all appreciate how incredible he is even more lately, because he’s shown a bit more emotion on court and he’s become a father so he seems a bit more human, more relatable. That makes what he’s doing seem even more amazing.
Yes, I really hit with him when he was 15, during a tournament in Basel, and I knew then he would be good, but not this good. If he stays healthy, it will actually be a miracle if he doesn't win more Grand Slams than Pete [Sampras]. The way he picks his shots is unbelievable. He is fast, he has a great volley, a great serve, great backhand, great everything. If I was his coach, what can I tell him? He is a magician with a racket. Even when he is playing badly, which is rarely, he can still do things with his racket nobody else can do.
Goran Ivanisevic on the question if Federer is destined to become the greatest player of all time.
Well, I think when I look at Roger, I mean, I'm a fan. I mean, I'm a fan of how he plays, what he's about, just the fact that I think he's a class—I don't know him personally, but seems like he's a class guy on and off the court. He's fun to watch. Just his athletic ability, what he's able to do on the run. I think he can and will break every tennis record out there.
Oh, I would be honoured to even be compared to Roger. He has such an unbelievable talent, and is capable of anything. Roger could be the greatest tennis player of all time.
Rod Laver, winner of 11 Grand Slams, considered by some the greatest player to ever play the game of tennis.
Roger's got too many shots, too much talent in one body. It's hardly fair that one person can do all this—his backhands, his forehands, volleys, serving, his court position. The way he moves around the court, you feel like he's barely touching the ground. That's the sign of a great champion.
The best way to beat him would be to hit him over the head with a racquet. Roger could win the Grand Slam if he keeps playing the way he is and, if he does that, it will equate to the two Grand Slams that I won because standards are much higher these days.
Rod Laver, speaking ahead of the 2007 Australian Open final against Fernando Gonzalez.
He's the best I've ever played against. There's nowhere to go. There's nothing to do except hit fairways, hit greens and make putts. Every shot has that sort of urgency on it. I've played a lot of them [other players], so many years; there's a safety zone, there's a place to get to, there's something to focus on, there's a way. Anything you try to do, he potentially has an answer for and it's just a function of when he starts pulling the triggers necessary to get you to change to that decision.
He hits that short chip, moves you forward, moves you back. He uses your pace against you. If you take pace off, so that he can't use your pace, he can step around and hurt you with the forehand. Just the amount of options he has to get around any particular stage of the match where maybe something's out of sync is—seems to be endless. His success out there is just a mere reflection of all the things that he can do.
There's probably not a department in his game that couldn't be considered the best in that department. You watch him play Hewitt and everybody marvels at Hewitt's speed, as well as myself. And you start to realize, `Is it possible Federer even moves better?' Then you watch him play Andy [Roddick], and you go, `Andy has a big forehand. Is it possible Federer's forehand is the best in the game?' You watch him at the net, you watch him serve-volley somebody that doesn't return so well and you put him up there with the best in every department. You see him play from the ground against those that play from the ground for a living, and argue he does it better than anybody.
He's a real person. He's not an enigma. Off the court he's not trying to be somebody. If you met him at McDonald's and you didn't know who he was, you would have no idea that he's one of the best athletes in the world.
I think there's—he's the main guy and then there's probably four or five of us that are—I don't know. Maybe we need to do just a tag team effort or something, join forces, you know, like Power Rangers or something.
Andy Roddick, after losing to Roger Federer at the final of Cincinnati 2005.
[In the modern game], you're either a clay court specialist, a grass court specialist or a hard court specialist … or you're Roger Federer.
He hasn't changed a bit. He hasn't been arrogant in the locker room. He never is. That's great to see someone that does it with class. He doesn't intentionally get in anyone's face. He doesn't put people down.
I thought Ellsworth Vines and Don Budge were pretty good. And Gonzalez and Hoad could play a bit, too, but I have never seen anyone play the game better than Federer. He serves well and has a great half-volley. I've never known anyone who can do as many things on a court as he can.
I am so proud to have him around. It is very pity that I am not able to play with Pete Sampras, but it's okay; I can see Federer on the tour. I could tell my grandson someday that I have competed against the greatest player on the planet.
Today I was playing my best tennis, trying lots of different things, but nothing worked. When you're playing like that and he still comes up with all those great shots you really have to wonder if he's even from the same planet.
Just about everything he does is pretty impressive. So, yeah, 50 titles at any age is impressive. 50 titles at 26 is incredible. 50 titles with 11 of them being Grand Slams, and I think now 14 being Masters Series, that's just phenomenal.
James Blake after their final in Cincinnati 2007, when Federer won his 50th title in the ATP circuit. 
I can cry like Roger, it's just a shame I can't play like him.
Andy Murray, after losing to Federer in the Australian Open 2010's final.
No way I would be a journalist. You guys have tried to kill Roger - often. But he's always come back and proved you wrong. So one thing I would not do is make the mistake of saying Roger is dead.
Rafael Nadal, when asked what he would write about Federer's decline if he were a journalist. 
I never can beat Roger, he’s too much for me… but the Senior Tour, I will beat him then! He’s the best of history and I’m very lucky to play the best player of the world.