Spoilers, by nature, ahead.
It's an incredibly common trope, especially in romantic comedies (or any form of fictional media with a romance sub-plot) for the couple who are going to get together to have some sort of dislike, friction, or reason to think of each other as enemies from the get go.
Similarly, the "competent rival" or "rogue who's just in it for personal gain" in chapter one is likely to be the best friend by chapter omega (possibly so they can be killed off by the "real" bad guy to establish them as a serious and evil threat) or the one who comes around morally and swoops in to save the day at the eleventh hour. Siskel and Ebert had an outline of Tom Cruise's early movies that suggested that "proto rival who becomes best friend" was a common element in a great many of them.
Less talked about is the opposite, which is becoming in some ways every bit as predictable. If someone is nice and friendly from the beginning- especially if they're in some way the superior of the protagonist they're being nice and friendly to- dollars to doughnuts, they're the villain or a traitor.
Liev Schreiber's character in Salt is one example. Oh, he's her superior. And he treats her with respect. And they have this nice kind of banter with each oth- he's going to be trying to kill her before this is over, isn't he?
Krysten Ritter's novel Bonfire has an example that's so obvious (in an otherwise pretty well-written yarn) that it's painful. Listen, lady- if you're in this kind of novel, and someone asks you if you've told anyone else about the big conspiracy before arranging to meet you somewhere private... And they're part of the evil conglomerate you've come to town to investigate, no less...
It was also one of the few things that disappointed me about Coco. We were so close to getting through the movie without having a real villain. There was plenty of conflict to be resolved without adding one at the eleventh hour. And yet... Some cliches, Disney apparently can't let go.
Anyone else have examples come to mind? Or for that matter, subversions?