Doom, Quake et al also have incredibly fast FPS (frames-per-second) rates, which adds to the puke-inducing feeling.
But going back to the 'why own movies' theme, i'd even go as far as saying that - just like owning albums for one or two particular favourite tracks - I own some movies that I rarely watch all the way through, but may occasionally just watch a certain scene from.
This can be for many reasons - because i'm in the mood for something funny, loud, stunning, awesomely loud - or just because i'm running in some new kit and want to use a particularly effective test scene.
It's like one of those Channel 4 '100 greatest movie moments' shows without the cheesy presenter, annoying adverts and films they feel they have to add....
I do it with concert DVDs and TV shows, too. Nothing like a blast of Suspicious Minds from Elvis: That's the Way it Is after an evening out!