Earlier quoted context omitted.
Depression doesn't care how awesome your life is.
Sometimes an awesome life can actually make it harder. It's easy to justify being depressed when you have a crappy life. (even though your depression probably doesn't have some cause like that) "I am depressed because I am living in a bad apartment in a bad part of town, working a bad job. If I get a better job and can afford a better apartment, I'll be happy." Assuming you have some hope for that happening, that can…
Not only that, but it becomes very easy to tell yourself that you don't deserve success. It's easy to look at your life and say "I haven't really worked that much harder, lived that much more virtuously. I don't deserve this, this should be someone else..."