What is the oddest or most unnecessary added scene in the movies that's not in the books?

For me, it's the detour Aragorn takes during the Rohan battles. He rides off and falls off a cliff and everyone thinks he's dead, then reappears and everyone is happy. It adds almost nothing at all to the narrative does not advance and IMO makes no sense. The only thing I can imagine is that it gives him a chance to dream of Arwen. But overall it's a waste of valuable movie time to me. I guess Jackson just needed filler.