I don't like it when a game or movie or novel's events contradict the logic of it's universe. For example I don't like it when the Normandy gets from orbit to the planet surface in a few seconds. But if it's explained and is consistent with the established universe, that's fine. For example if a magician casts a fireball and we've established that magicians use magic and can do that sort of thing, that's fine. Without elaborating too much, this is why I dislike the argument "You're worried about realism in a game that has dragons in it?!" that comes up when I complain about something unrealistic IN RELATION TO THE UNIVERSE IT'S IN. ie. I'm happy to accept anything that is explained and doesn't contradict established concepts/lore, but I don't like it when these are broken without reasonable explanation. Which is why I don't like things such as, say, hand-waving where time travel is concerned, or characters knowing things they have no way of knowing, or space vessels acting in ways the Codec says they shouldn't...!
And btw, I don't like it when crime shows play around with things like voodoo or split personality disorder or something and then fucking shrug their shoulders at the end and say "Maybe it was, maybe it wasn't".