I'm a little ticked off right now. I've been watching videos of Art Tatum and other pianists playing his music, and they make me mad. Why? Because they remind me of all the work I have left to do. Let's see if I can be any clearer.
First, Art Tatum was so doggone good. He played with an ease I've never seen in any other pianist, and set the bar of proficiency unbelievably high. He's the standard by which I judge my technique and musicality, which means I have to practice a lot more. This makes me mad.
Second, while the other pianists playing Art's transcriptions are good, I don't feel they capture the spirit of how he played. Naturally I think I can do better, but only with more practice. More anger.
A healthy dose of irritation can be very motivating. Maybe you're trying to match someone else's level of excellence, or maybe you're trying to show what real excellence really looks like. Get mad and get to work.
P.S. There's a fine line between getting good to fulfill your potential and getting good to feed your ego. I'm advocating using anger to fuel the former motivation.