Thing is, and this might shock some of you...me either. To a point.
I enjoy certain MOMENTS in all three movies (there is no III and IV! No, shut up!), but as a whole? Well, here's a quick thought on each of them:
Superman I: I tend to skip it to when he arrives in Metropolis, or at least up to Smallville. The Krypton stuff is so dull and dry. Then, there's the ridiculousness of spinning around the world until he goes back in time.
II: Everything with Zod and company rocks. My favourite movie moment of all time is when it looks like Superman has lost and them, crrrrrack! But the mind-wiping kiss? The "fight" in the Fortress at the end (cellophane S!), a lot of really dumb comedy moments, etc. The Director's Cut, minus the ending, was a hell of a lot better.
Returns: The stalker aspect, the kid, the repeat of moments from the first two moments to be "loyal" to them, etc. But then the action was great and given the kind of production Hell it went through (Burton's plans, Kevin's Smith's anecdote), it could've been a LOT worse.
My favourite renditions of Superman? All Star Superman, along with The Animated Series.