The Moto G was never a fast phone, but a new thing it started to do towards the end of its life was OOM kill the mp3 player if you backgrounded it. At first it was if you did something heavyweight, like start a game. Then it was browsing an ad-heavy site. Then it was if you opened the web browser at all. This, plus the usual Android lag, bad battery life, intrusive Google Botnet stuff.
The tipping point was this. I walk to the coffee shop with music playing. I order, sit down, start reading. There's an amusing line in the book, so I take out the phone to take a picture of it, which kills the music player. Then a Google Maps notification pops up asking me to add the photo to the coffee shop's Maps page.
I think, why the fuck am I still using Android? I know Google tracks me everywhere I go, but do they have to be so obvious about it?