I saw a clip in an ad on television about this movie that looked really good. I think it was about a kind of creepy guy who worked some place (i think he had glasses and a white shirt on) and then he saw a family, and then he began kind of "following" them, and adapting into being one of them kind of. And that's all I saw, I think the lead role was a known actor because I remember thinking "oh he's in it? I must see it!"
I dont know if it was Jerry Seinfield or someone that reminds me of him? It's just a guess