I guess last crusade was okay, pirates 3 seriously needed some subtitles to make more sense, the matrix revolutions proves we should have taken the blue pill and ignored the Wachowskis, I have never seen Superman III and think the whole superman franchise is hokey, I didn't really like back to the future III, and jedi is relatively good when it comes to threequels. I'm surprised no has mentioned Revenge of the Sith, maybe because it's the PT. And I'm sure transformers: dark of the moon will be tossed around after that comes out, but the last two were typical Bay films: overstylized, noisy garbage.

Thinking on a philosophical point, maybe the reason third installments suck is that the universe is binary (one view and its opposite view), and no human being can conceptualize a third view, so we have to rehash or go off the deep end to in the third installment of a franchise.