I never even thought of this before as a borderline thing, I just always thought it was a social anxiety issue. Very enlightening! I feel the exact same way, I pretend I am someone else with others the entire time in fear of them really seeing me and rejecting all of that. I wear a mask and I always come off as a people pleaser, to strangers at least, where I always agree with their opinions (rather pretend to) and seem overly friendly yet very reserved and quiet. I guess I just think of how I want to be treated as well and often find people rude in general, so I don't want to be that way. I want to come off as friendly. But behind the mask, I feel a lot of resentment and anger towards those that seem to come off as rude or inconsiderate. I can't speak up against them but at home I'll feel overwhelmed by anger. I understand why we burst at times if we're constantly suppressing ourselves and what we feel because we don't know how to show it in a stable, normal way like everyone else.