Weekend
It felt so lifelike and real: the way of filming, the sound, the acting. I actually felt like I was intruding at times; which felt like a much better version of a fourth wall break. This all made me really transfer into the story, like a ghostversion of myself. I've never actually gotten that feeling from a movie before.
Edit: Andrew Haigh is in my top three of favourite directors. He also made looking, the best series ever made, and all of us strangers, which is the most heartbreaking horrormovie.