I have a concert in six hours and:
a) I've got a cold sore on my lower lip, that looks terrible right now
b) all the 3 bass strings on my guitar make absolutely awful buzzing sounds that I really can't explain (it happens on some guitars, but this guitar is brand new, and I've played with new strings that the guy I bought it from put on right in front of my eyes, and it had no problem at all, in fact I even liked the fact that it didn't make any buzzing sound at all!)
I hate when things like this happen unexpectedly. I hate them.