I ate just a little too much at each meal, drank booze liberally without allowing for the extra calories in my planning, and didn't move enough.

I had a lot of the stressors on the list but the ultimate culprits were my poor choices. I'm not saying that to badmouth anyone else, as I realize that some things are partially or totally beyond one's control...hormone wackiness and medications, to name a couple of common causes. But for me, it was my own damn fault.