And again, what's to ring?
I also own all of the Friday the 13th movies just to have all of them (Although in those cases I hadn't actually seen anything from 5-10 when I got them...), even if Jason X is one of the most hopeless movies I've ever seen.
It's just what some people do. Is it silly? Sure, but it's a valid excuse.
And hell, sometimes I just get the urge to remind myself about the film, and sit down and try to watch it. I never get through it, but it gives me enough of a reminder not to see the film again for a while.