I set my phone (LG G2 AT&T 4.4.2) down on the desk as I came in from lunch. And it gave the AT&T power on sound. It had been shut down somehow during my lunch break. I didn't purposefully shut it off, and I don't see how I could have done it accidentally. It is in Spigen Slim Armor case.
Is there something Event Viewer-like that would show me any error or reason for shutdown?