They don’t always need to be comfortable or straightforward. In fact, they shouldn’t be. No matter what the medium, you expect the author to fulfil a sort of unwritten agreement that, at the end of it all, you will have gained something from taking the time to engage with their story. That could be as simple as learning something new (as the classic parables of old do) or it could be more personal (learning deep truths about the nature of life or society through the eyes of a character you identify with).
Endings and why some of them leave us dissatisfied have been on my mind recently, since finishing the finales to several video games and fiction series. Both mediums have presented me with examples of endings that livid up to my expectations and others that fell short.