Bill Zebub
“It’s probably Matt Mercer’s fault.”
I don't see falling of a log and being tricked by a troll as different, as far as agency is concerned. They are both events that occur, in the fiction, to the PC.
You are right, by that definition.
Other things that are no different from an agency perspective: coveting a magic item, being moved by a sunset, wanting to learn a new spell, deciding to enter the scary dungeon, or even leaving the tavern in the first place.
I want to know where the line is: when do I have agency, and when does the game tell me how my character should be played?
When I suggested something similar upthread, your response was (I paraphrase) that it depends on the amount of narrative surprise resulting from the decision point. But that's entirely subjective.
My opinion...and I've yet to hear an convincing argument to the contrary...is that the only distinct, objective line of division is that your internal thoughts and feelings, and thus the actions you attempt to take, including the things you say, are objectively different from the results that your actions have in the game world. Your character is free to think that you are a freakin' ninja, and your response to the troll pushing you may be to laugh at them and (try to) do a triple backflip onto their head, but you don't have control over the outcome of that attempt.
And my preference is that this clear line be the line, so that in the absence of specific rules that cross that line there's never any question about who calls the shots, player or GM.