Easy to say and hard to do I know.
Quite a while back I made a decision that I wasn't going to give away my peace of mind to someone else. I wouldn't give anyone the satisfaction of rattling me and guess what happened? I blend in better than ever.
Passing isn't being taken for a genetic woman every single time. It is instead being perceived as a secure and dignified person who is dressing and behaving as they like. That is what passing is. Many older transgender women don't pass and ironically some people who crossdress do so very well. It is about dignity and grace above all else.
But no matter the quality of presentation, all can be undone with nerves which is why we should avoid them.
Never give away your peace of mind to anyone because they haven't earned it.