People have been asking this same basic question for years - heck, vast swaths of literature have been devoted to this basic question. The shortest answer I can come up with is that, if you look at it with a wide enough lens, the world fundamentally sucks. War, terror, corruption and the like are part of the human condition so as long as we exist, so will the darkness. In my mind, the key is to turn off the news, shut down a web browser and simplify, but my key likely won't work in your lock.

Have you ever read The Sun Also Rises?? Hemingway struggles with similar questions and he's a far better writer than I am!! :)