I have also returned a game outside of the 2-hour window; No Man's Sky. I bought it a few years ago once it had shaped up from it's initial disastrous release, but 3-4 hours in I realized what the loop was going to be the whole time and didn't want to do any more of that. I explained myself in my return request, and the next day I was credited for the purchase.

My worst Steam experiences are the comment sections by far.