Halloween-No slasher fans might be up in arms over this one as maybe a bunch of people love the later sequels. Some are alright and while I like the second film I would not have been sad had they stopped after the first film. Oh, golly-leave something open ended and up to your imagination-the horror.
Superman with Chris Reeves-The first two were great and I flip flop between which one I prefer a lot.
Let’s face it three and four were horrible so the franchise ended up batting .500 because the later sequels were so bad.
Planet of the apes-first run-The original is a classic and there is no doubt about that. The second film had a few new ideas but really the end results was a very mediocre sequel. The third film was just a reverse angle of the first with apes taking the place of the humans but it was decent. Now the forth film Conquest of the planet of the apes saw the series charge ahead and really take some risks. It was a fine film and I’m so glad they ended on that one-oh, wait they didn’t. Nope the next year they cut the budget even more and all the passion and energy of the forth film was followed up a lukewarm sequel in Battle for the planet of the apes. They should have quit before number five as instead they only had a three out five success rating and they finished on their worst film.
Batman-The one’s that Burton guy started-The 1989 films had some flaws, but it was exciting. At the time I had no reason to think the follow-up would stink up the theater yet it did. The third film was a little better or not as bad. Yet the forth film was a big-budget stinker as still has people shaking their heads at it.
***Feel free to add your own examples.
Lasers, monsters and barbarians oh, my! 
