If you want to understand my perspective on The Exorcist a bit better, you should read this. Two more points: 1) I've witnessed a few things that are similar to scenes in The Exorcist (I won't get into that here, except to say I had a very colourful upbringing, including being part of a cult at one point). 2) I think Friedkin's unfussy documentary style, and the fact that the film was considerably less overblown that other demon possession films that didn't take the subject seriously added to how disturbed I felt when watching.

More here: https://fanfare.pub/my-journey-of-faith-and-the-exorcist-84a74de51846