"There is no bigger hassle than being asked all the time these questions," said the 29-year-old Swiss after losing a Miami Masters semifinal to rival and nemesis Rafael Nadal 6-3, 6-2 on Friday.
"I don't know how many times I need to answer until I just say I'm not going to answer it anymore. I know that I can do many more things in the game," said the winner of a record 16 Grand Slam titles. "Sure, it's disappointing losing a match like tonight, but those are the matches I work extremely hard for in the off season and practice.
"I'm very excited by what's to come still."
With the most obvious successor to the American Pete Sampras, who all but burned out before the age of 30 and found the sport a struggle in his last few declining years, Federer feels he still has plenty to prove after setting many of the records which stand in the sport.
"I don't feel like I'm 35 like you guys make me sound I am," he told media after the loss. "I'm still only 29, and I have many more years left."
Federer holds a 22-4 mark this season, losing three times in 2011 to on-fire Serb Novak Djokovic and once to Nadal, who stands 15-8 in their series. The semifinal was the first time the pair had played in the US since 2005.
Federer still maintains his fighting demeanour despite the loss on the day wife Mirka Vavrinec celebrated her 33rd birthday.
"For me, these are not big setbacks," said the Swiss of his recent losses to Nadal and Djokovic, who will meet in Sunday's Miami final. "I wish I could play better right now against those guys, but it is what it is.
"I'm excited going to Monaco now, he said of the clay season which starts in nine days in the principality. "I'm going to fly there directly and prepare as well as I can for the clay-court season.
"It's a big swing coming up now in Europe, so that's the mindset. I want to do well and I want to do better. I got the opportunity in a couple weeks already."