When I had first sat down to watch Romero's "Night of the Living Dead" (from 1968) - I was all prepared to be totally let down (in a big way) by this amateurish, low-budget zombie picture.
But - Hey! - As the story began to start rolling along and picking up some steam - (Well! - Surprise! Surprise!) - It actually turned out to be a genuinely terrifying movie-experience that (regardless of its noted inadequacies) still managed to hold up (to some degree) 50+ years down the road.