Shyamalan

Pretty much the only film of his I'll give credit as a finished work that accomplished what it promised/intended is The Sixth Sense. Unbreakable minus the last five minutes could have been pretty good, but it was the beginning of a long series of let-downs. His other films are a mish-mash of disparate memes that never get properly tied together and none of which are fully realized, with increasingly lackluster twists and, it would seem, deliberately stilted acting.

As a disclaimer, I haven't seen anything since The Village, but from all I've heard it's been downhill from there.