Dani Filth - the rest of the band has some talent, but he needs to step out.
Good Charlotte/Blink 182/Simple Plan/Linkin Park/My Chemical Romance/etc. - just shut up already. When your daddy said to get a real job, you should have listened.
Slipknot - seriously, you can be angsty with fewer people. Besides, 9 people should be able to make at least slightly complex music.
The White Stripes/The Darkness/Coldplay - go back from whence thou came, foul beasts. Your vocals smite my ears and your lyrics slay my love of British music.
Proliterean - I only know you for your "Creep" cover, but never, EVER come within 50 miles of me, or I cannot be responsible for my actions.
Generic rappers - for Christ's sake, have some originality, people. Everyone learns your lyrics quickly because we've all heard the same thing since Snoop's debut. Say something else! Hell, even old-style gangsta rap would be a nice change.
People who scream more than sing - if I can't understand what you're saying then I don't care.
I might as well use this thing now - everytime I try to explain my issue with something I get told to come here instead anyway.