I dealt with a lot of depression as a teenager, and still dealt with it as an adult for a time. It's easy to be critical of yourself, especially as a teenager when you don't really get why things are the way they are. You have in your head an idea of how things should work, and how you want things to work, and it's difficult to understand why they don't go that way. But everything has its purpose, good and bad. Every life is valuable.