Anything that can get my adrenaline pumping, which generally only happens with multiplayer games when I am facing a human opponent. Dark Souls is a great example for me, here, because the single player gives me that rush for a while but eventually I'm able to breeze through every boss and enemy in the game with minimal effort, so going into invasions and getting sweaty against a host and his 2 OP phantoms is the only way to get that rush again, because, generally speaking, other players can think so no two opponents are really ever the same.

I actually kinda wonder now what the flow state even feels like to others who suggest things like strategy games or puzzle games. To me, it's like that fucking hyper focus the protag has in the movie Wanted. Crazy Lazer focus on whatever action is going on, and it's just like... Automatic. No thoughts. Just actions. So I'm really curious how it might manifest in something slower paced like Civilization and what not. Or even how some folks can enter that state via meditation. That sounds awesome and I wish I could trigger it with something else.