What lessons have you learned from depression?

It's funny but I only realised recently that what I have is depression, even though I've lived with it my entire life. And once I realised that I started to think about how I feel this way, what combined experiences of my childhood and adulthood that had caused this feeling of emptiness.

Clinically dissecting it makes me feel better, I guess... makes me feel like I have control over it, rather than the other way round.