Few things in life are harder than wrapping up a story in an interesting way while also keeping the viewer hooked for any potential follow-up. Whether it's a movie, a video game, a book or a TV series, there are many ways to stumble right at the finish line. Honing in on TV, in some ways creators might have realistically already crossed the finish line, only to then fall flat on their faces when the next season of a series rolls around.
Not only does it hurt when these things happen, but it's even worse knowing that the cliffhanger that came before was so incredibly good that you couldn't stop thinking about it for days, weeks or even months. You'd expect the resolution to be on par or even better than what came before, but that is not always the case.
Sometimes series do you dirtier than a pig rolling through the mud when it's hot outside. Sometimes the resolution is just plain awful and it leaves you in a state of uncontrollable rage. Not because they were just that bad, but because these cliffhangers failed you on a personal level.
Be aware, full spoilers for these episodes follow.