What movies have the best background scare? Where you don't notice the danger lurking in frame until the rewatch?

This is not the "Jump Scare" where the boogeyman lunges at the victim from the ether. No, this is the "Where's Wally" scare where the boogeyman was pretending to be a prop or an extra. Neither the camera nor the score pays any attention to them hiding there.

I'm not going count how many fecking Insidious movies they've made, but this subtle moment from the first is a good one. If you want to be spoiled, the answer is 35 seconds.

EDIT: Slightly less shitty quality of same clip.

https://youtu.be/xjARWT6Qua4?t=32

Michael "Not Mike" Myers is a camera shy fellow, but he is proud of the station wagon that he steals. It even pops in the background of scenes that don't focus on it. The man himself is quite nervous, choosing to wait patiently outside the window while the leads talk and argue. God bless him does the man try to make an entrance, despite his bashfulness.

Noroi: The Curse is a found-footage horror-film that twice makes this trope a plot point. The lead is a paranormal investigator, and he looks back on his own footage to catch a glimpse of something his cameraman filmed unawarely. The first time is when he tries speaking to a hostile and disturbed woman on her doorstep. She slams the door in his face, and they turn to leave. But the footage catches a second of a boy's face peeking through a window upstairs as they go. The woman doesn't have any children.

Later we see a TV show where another gang of ghost hunters invite an actress along for a laugh. They do get spooked loafing around the woods at night, but they fail to notice the hostile figure standing a few feet away in the darkness.

This trope was the bread and butter of the Slenderman, but he's not popular any more these days. He ironically became over-exposed, and his name was invoked in numerous controversies. He now sits on the sofa in the background watching TV, vainly trying to drink beer and shovel crisps into his non-existent mouth.