as a former employee of an ebay based company, my favorites were:
- feedback whores. (i paid you two seconds ago, i want my feedback NOW)
- feedback hostages (ship it overnight at no extra cost even though i paid 10 bucks below cost because you did not reply to my email within three seconds or i'll give you a negative!)
- people who can't read (why is your shipping that much? i won't pay it! well uh you bid on the auction, therefore you read the terms.)
- people who need immediate gratification (please reply in the next twenty minutes.) (or the one guy that left a neutral because we didn't respond to his email over the weekend. when we were CLOSED.)
- people that kept telling me i ruined (insert holiday here). it was NOT my fault they were procrastinators and tried to order something two days before a holiday! i got it out! you suck! (at christmas i was really hostile and couldn't stand another living soul and when people started yelling at me over the phone i really wanted to yell back at them soooooo badly.)
- people who send personal checks, and expect the item shipped immediately. actually, people who send personal checks period. get a money order.
i had monster lists of why i hated ebay bidders, but since i don't work there anymore my anger subsided greatly. hehe.
EDIT: people who would not pay, have a negative left for nonpayment, and then give us a negative back. i loved them the best.