Well "Carrie" was a good film but the sequel "Carrie: The Rage" (or something along those lines) was absolutely crap! Also what did "Halloween 3: Season of the Witch" have anything to do with the rest of the series??
I agree about the third part of back 2 future but I loved the 2nd as I saw it in cinema when it came out when I was about 14 and it was one of the first films with special effecs like that and the whole sci-fi time bit I loved. It was the fact that you could see the two sets of haracters at the same time I thought was good
oceans 12 was laughable ! one of the worst plots to a movie ever.
also agree with highlander sequels too - 1st one was amazing at the time and i watched it many times but it has aged really badly and i cant watch it now.
I'm suspicious of most sequels except those which are obviously an extension of a longer story, like the Godfather, Lord of the rings etc. Incidentally, I hated Lord of the Rings 2.