Scared the crap out of me....when I was 7.
I think I had a very valid reason to be scared of this when I first saw it. First off, there was a cemetery on the end of the road I grew up on. It was possible, in my very young mind, that that cemetery had previously existed on the end of the street that I lived on. In addition to that, my neighbors were currently digging a pool in their backyard. To top it all off, it was raining. Spooky circumstances, indeed!
Another thing that never fails to be scary, is that fucking clown doll! In my opinion, there are few things scarier than an evil clown. "Can't sleep, clown will eat me! Can't sleep, clown will eat me!"
Good thing I didn't know then about the supposed Poltergeist Curse.
Really, the film is pretty mild, by today's standards, even yesterday's standards and certainly by Tobe Hooper's standards. It does bring back memories...and to date, the only thing my Dad has found buried in the yard has been a dead horse. (No shit, he found a horse skeleton while digging in the front yard.)