I lasted about 90 seconds before deciding 'this is bollocks and I bet they're going to have some fake ghost thing at the end' and fucking off to listen to music. As cynical teenagers do.
The then boyfriend completely threw me at a later date when he insisted that everybody was terrified of it and it was utterly real. He was there when I flounced off and agreed with me, but such is the pressure of this shite, people feel that they have to go along with the narrative that's been created by TV talking knobs heads programmes/schedule fillers.
When I went with a later boyfriend to see The Exorcist (at Hallowe'en, naturally), I watched it, could see that it was probably shocking to the audience at the time to have a girl appearing to say swearwords and doing blasphemous things with a crucifix, but it didn't bother me at all. That boyfriend was disgusted with me because apparently, it was absolutely terrifying.
Thing is, it's been a marketing hype thing since forever to go on about people collapsing, vomiting, having heart attacks (nobody ever mentions the times when people with heart disease have heart attacks when watching Angus, Thongs and Perfect Snogging or Peppa Pig The Movie) and the like. It's just that people can be very stupid suggestible, especially when in large groups such as at the cinema, so they've heard the marketing, see others who also believe the marketing, then get, frankly, a bit over excited.
I've never watched the so called classic slashers other than Halloween 1-10,000 (or whatever it is now). I had no interest in 80s movies such as Nightmare on Elm Street, Candyman, Child's Play, Bride of Chucky (did watch Gremlins and still can't see how it was thought to be an 18), couldn't be arsed with Bleurgh Witch, think M Knight Shymalan should probably give up his day job and go and do something less boring instead and actively despise torture porn for everything it stands for. But a proper religious horror movie is great, as are creature features.
None that changes the fact that it was all hype, some people bought into the hype too much - and yes, people are exaggerating about The Exorcist.