Let it be known that I am generally a messy person, but my iTunes is almost perfect.
Things that bother me in iTunes:
1) Singles. Complete albums only please.
2) No album artwork. Album artwork is meant to go along with the music, so why not have it?
3) Low quality music. I just started re-importing my music using the Apple Lossless encoder. Yes, you can notice the difference.
There are a bunch of music people on here. Do you have crazy OCD when it comes to your music?