I remember not liking The Birds at all the first time I saw it. I was promised a scary movie, not... whatever that was. It didn't even have an ending.
Of course, I was a stupid kid the first time I saw it. I'm still not as big a fan of the movie as some of Hitchcock's other stuff, but there's a creep factor here that's hard to put your finger on.
Take this scene, for example...