“I don’t want to be America’s swell guy in music. I just want to play and tell the truth. Every time I sit down at the drums, I have enough ego to say that what I did last night was good. But not good enough for tonight.
I don’t play as well as I want to play. And I’m a bitch! I have never achieved the level of complete satisfaction. It’s really impossible. That’s what I mean when I say, ‘set a goal’. But you never reach it because it’s always changing; you want more and more from yourself. Smugness is your enemy. It’s over for you as an artist if you think, ‘Hey, I’m so good I don’t have to try too hard.’
Art Tatum didn’t play as well as we wanted to. Oscar Peterson, ‘the man’ on piano, is still working to create and execute something that doesn’t seem possible. And he’ll never stop. He’ll keep trying to be the most complete, the best artist possible. I’m sure he, too, says ‘I’m not as good as I want to be.’
There’s too much control in our day-to-day lives. We’re told what to read, what films are good for us, what music we should listen to, how fast we should travel on the highways. We’re programmed by pressure groups and critics when it should be left to the individual to make up his own mind about things.
You gotta be what you are. You can’t be what somebody else would like you to be. I’m myself, and what I think I like. The nicest part about it is that I know who I am, and so I don’t have to grope for identity.” 
Buddy Rich, one of the most influential drummers of all time, said this in 1974. It holds true.
I come back to this quote when I feel like I'm pushing myself too hard. Or self-doubt kicks in. Or comparisons start to happen.
Maybe it will help you too.