If I'm in a specific mood or something significant is happening in my life, I'll do a self portrait to capture it. It means something to me, it's like a moment in time that I want to remember. When I look at it, it brings back that feeling and the memory of whatever events surrounded it. I don't do this for "happy" moments but rather moments of unpleasant experiences or situations I learned from. Nostalgia is a powerful thing and doesn't always signify the times you wish you could go back to.