My playstyles are
Walking around catching and spinning
Cycling to a place then pulling out my phone for some egg/buddy distance and checking nearby for rares
Walking past a section of gyms looking for easy takeovers and working my way to more gold gym badges. By the way it's the opposite for me, I make 50 coins daily now instead of the 0-20 I used to make with the old system.
Going to a raid with people from my neighborhood
My goals are
Fill the Pokédex
Get as many gold medals as I can
Collect neighborhood gold gym badges
Collect high IVs preferably 100% of as many Pokémon as I can
Try to have only one of each Pokémon in my inventory, with the exception of Shiny (unless the shiny is higher IV than the normal one, in which case I'll only keep the shiny)
What would it take for me to quit? A lot. It would take the app to not work at all on my phone anymore.. but then I'd probably just go buy a phone it does work on. (I use an iPhone 6 by the way, I crash all the time)