I hate movies where there's just that one guy who's (apparent) sole purpose is to piss you off and is consistently a thorn in the protagonist's side.

Worse still if when the protagonist gets the upper hand on him, he ends up letting him live because he's "not worth killing".

An example of this I can recall would be the German dude who shows up every time Indy finds something valuable in Indiana Jones: Raiders of the Lost Ark.