Trilogies that will sadly never get finished

It seems like just about every new movie is looking to be turned into a franchise or a trilogy these days. While it makes sense for some movies (like superhero stories) to receive multiple sequels and be part of a shared universe, it doesn't always need to happen. (If you saw The Hangover, you get the idea. If you saw any of the sequels to The Hangover, you're jumping from your seat and shouting, "Preach!") Of course, sometimes movies just aren't commercially successful enough for a studio to greenlight a sequel, even if the sequel was going to be really awesome and even if it does leave the previous movie on a totally unacceptable cliffhanger. But people vote with their wallets, so there are plenty of studios with planned sequels that never saw the light of day. Here are some of the movies that will never see their trilogies completed, no matter how much you beg.