I remember trying to read this in high school, early high school and finding it boring. I think I quit right about the time Eleanor stole her own car. But I am trying again to read it now. I am having troubles for entirely different reasons.
It is scary as fuck. Took me forever to get to sleep for fear I’d hear noises and then I had nightmares and I woke up at 2 to just lie there nervously in my bed hoping to not hear noises or see things.
And it’s pretty much perfectly written. So, you read all this terrifying stuff then you feel like you have to go back and try to figure out why, exactly, it’s so terrifying. It’s like seeing a ghost in a room and forcing yourself to go back in the room to investigate. I barely have the constitution for it. But so far, nothing has really happened. Some doors have shut.
And yet, holy shit.
And holy shit because Jackson gives you a perfectly plausible explanation at first–none of the doors are plumb. Okay, but when they bloc the doors with a vase or something?
I totally see why this is a classic. It is pretty much perfect. And the thing I think is really great is that there are so many times when Jackson appears to be breaking the “show don’t tell” rule, because her characters pretty much blurt out all of their motivation. But then you realize, no, she’s really showing you something important about these characters in what they say, even that that’s the thing they think to say.
But damn, it is scary. I hope the second half holds up.
Tiny Cat Pants 
Also a really good movie. The 1963 version, not the drek remake from the 90s. Julie Harris and Claire Bloom among other good actors, filmed in glorious balck & white, screenplay by Shirley Jackson, and really, really scary. All of it done with sounds and suggestion. Amazing. I saw it on the big screen when I was 11. Couldn’t sleep for a week.