What was the WORST SEQUEL you've ever seen??

I just watched Dark Knight and DKR, gotta disagree with whoever said DKR. League of Shadows were the best villains of the trilogy. DKR made Batman Begins even better as one complete story. Dark Knight was good, but the weakest in the trilogy IMO. It could have been a standalone film, and while Joker is an awesome villain, he wasn't as developed or focused on as much as I would've liked him to be.