I love what you said about feeling maybe more vulnerable when you are feeling low. I am the same for sure. As far as a coping mechanism goes with that insecure dum dum- keep reading. How did that nincompoop manage to be close enough to to be in your wonderful presence? Their mouth opens and insecurity simply pours out. I have a million ways to deal with such episodes, but I will start with one. This person is miserable. Plain and simple. Good people don't do that. Why would you believe that idiot, when all of us on your thread think you are something special.
I questioned myself for years but thank goodness came to the conclusion that I am so amazingly unique. Keep sparkling! And to quote a fellow threader, you are perfect just the way you are.