There are a lot of other good answers here. My 2c: People will use all kinds of tactics to get their way. Putting you under time pressure, bombarding you with

There are a lot of other good answers here. My 2c: People will use all kinds of tactics to get their way. Putting you under time pressure, bombarding you with a stream of precise facts and figures, making you feel slow and stupid and out of sync; these are all just ploys used by a hostile counterparty to influence your decision making. You need to learn to recognize these tactics for what they are and develop counter measures. Some "honorable" counter measures might be: demand to be sent the details in writing and promise a decision in a reasonable amount of time. Buy time by repeating back what they just said to you "to make sure you understand". Ask a lot of clarifying questions. Make your decision conditional ("I'll buy in if you can provide me with data set X that supports your direction"). etc. For less honorable counter measures just think of "bad meeting" tropes. Appeal to authority ("we can't make a decision without person Y here, or without committee Z signing off"). Bike shedding. Circular reasoning. etc. You really shouldn't make a habit of any of these, but sometimes when you're ambushed by a bad faith actor you're gonna need to fight dirty.