Last night I left my phone charging while I went to sleep. I did not have it updating while I went to sleep. When I woke up it was stuck on the LG logo and won't respond to the power button - it won't turn off at all, so I can't try a soft reset or anything else.
I have no idea what it was doing before it got stuck, as I didn't have it updating or anything when this happened, unless it can start updating on its own now.
My only idea is to just leave it until it runs out of battery and turns off on its own.