He just looks fucking brutal the whole time. Then, as soon as he breaks it, he reminds me of every little kid I've ever seen break a window. It's the classic "oh shit, my mom is gonna kill me when she gets home" look.
I must say though, I've gotten momentarily pissed like that a few times when trying to sing and my voice cracks or something... all I can say is, initially, it is very satisfying when you see and hear that you've broken something, and almost makes you angrier when there is no damage. That's before you slip back into reality and realize what you've broken...