For us, our group has been playing together in one form or another for maybe decades now, we all know each other fairly well and take turns GM’ing. Session 0’s for us usually tend to be character creation and some worldbuilding, but that’s about it. Some of the people I game with though tend to be less improvisational is what it feels like alot of the time. It’s just kind of how they are, I know it walking in.

Even if it’s a homebrew adventure they wrote, they have a tendency to just stick with what they wrote and won’t deviate from that. So if/when the PCs do something outside expectations, it’s inevitably molded or pushed back onto the rails, sometimes in more obvious ways. “Story beats” for them are unavoidable combat encounters that they planned for, so goddamnit, we’re getting into combat regardless of what the players do to try to avoid it.

And I try pushing out in different directions, I’ll GM and try running one shots with different systems, mechanics, or just switch up the generic fantasy stuff we seem to tend towards, just to do something different, but everyone still has their comfort zones with what they usually run and how they run it.