I've asked myself the same questions many times. When I start feeling like this sometimes I search online for good news stories so I can try to reassure myself that there are good people in the world. There's a YouTube channel called "RealLifeHeroes" that I'll watch from time to time, it just has a lot of great videos about humans doing amazing things for each other and animals. I know, it's kinda silly, but it can at least help pull me back from the pits of depression sometimes.