Mobile games succeed for me when they focus on taking simple taps and/or swipes and doing something fun and/or interesting with this simple scheme. Anything that's trying to emulate the full-fledged console experience on a phone is a waste of time. Like who tf wants to play Fortnite on the phone?

Alto's Adventure is a fun one to just zone out because I don't actually have to do much, but it still manages to impart a feeling of speed. Puzzle games that are polished like Hitman GO are satisfying and a good timewaster.

That being said, I don't typically play mobile games anymore because it's not much harder for me to bring my 3DS if I'm gonna be in a situation where I'd want to play a game on the go. And that's just a more enjoyable experience in general. The phone gets used for the occasional game of chess or crossword but that's about it these days.