Victims of poor referee'ing, judging and/or circumstance:
Phil Baroni vs Evan Tanner - UFC 45
Match is stopped seemingly prematurely because of a misunderstanding between Baroni and Larry Landliss. Landliss asks Baroni if he wants out and Baroni thinks he is asking if he is ok, and Baroni answers yes. Match is stopped and Evan Tanner is declared the winner
Gray Maynard vs Rob Emerson - Ultimate Fighter 5 Finale
Emerson came into the match with a rib injury which was exacerbated by several strikes in the first round. Early in the second Maynard slams Emerson which causes Emerson to tap, but the slam itself knocked Maynard out. The match was called a "No Contest" since neither fighter could continue.
Matt Hamill vs Michael Bisping - UFC 75
It's a close contest that goes the full 3 rounds. When the judges return with a verdict, it is split but gave Bisping the win. The lone judge who thought that Hamill one gave it to him 30-27, while the two for Bisping went 29-28. Many fans contend that Hamill should have won and kept his undefeated record. Afterwards Bisping's father was accosted in the parking lot of the England arena where the event took place.