Sometimes people commit suicide after something good happens to them, and those that knew them wonder why. It's because in depression, one tends to pin one's hopes on a single thing: "if I get this job, life will be better," or "once I get married, everything will go more smoothly," or "if I could afford a car that worked, I'd be happy." That sort of thing. But when the good thing actually comes to pass, the person finds that it doesn't shine any light on the rest of their lives. It only made a small corner of their lives better in a certain way. And so, seeing clearly now that one improvement isn't sufficient to give their lives that complete overhaul they'd been craving, they now realize the futility of that kind of hopeful fantasy. And, because depressed, they think that therefore there is no hope of any kind.
Anyway. I understand the viewpoint.