I remember in Revenge of the Sith, when the actor playing Vader yells "nooooooooo", at what is supposed to be the emotional climax of the trilogy, the theater roared in laughter.
I watched the first hunger games movie in a Thai cinema. There is a scene where Katness (is that the main characters name...) breaks up with her boyfriend for some reason, neither of them is happy about it. The whole theater broke out in laughter, I have no clue why.