Pet Peeve Trope
(watching a kung fu movie)
Buffy: Oh, give me a break! This is all wrong. See, first you would get the big guy, with a flying kick. Then you would take out all the little ones, bam, ba—see, now with the flying kick. From a dead stop! What's powering it, raw enthusiasm?
Riley: Hey Buff, maybe you ought to leave the work behind sometimes. You're not always on Slayer duty, you know?
Buffy: It would drive you crazy if we were watching an army movie and they were all saluting backwards and... invading all willy-nilly.
When a trope is either so played out, so stupid, or so racist/sexist/whatever, that seeing it makes some portion of the audience go berserk.
Sometimes this is due to Values Dissonance making a trope obsolete. Continuing to use such a trope when the underlying morality behind it has been discredited is sure to get some annoyed reactions.
Note that subversions and deconstructions are probably already playing too close to the line, and playing them with even a hint that they're being played straight will get certain people up in arms.
No examples, please; everybody's got at least one, and it's rare when any two people's Pet Peeves match.