I believe our *all-or-nothing*, *black and white* thinking makes perfect sense when considering BPD as a whole. 

Our extreme emotions lead us to mistrust ourselves and our perceptions, therefore we ruminate and overthink until we come to (what we believe to be) a logically sound conclusion. It isn't just a knee-jerk emotional response, it is the logical compensation for our unstable sense of selves/reality; a never-ending cognitive dissonance. It's a desire to put things in a box, give our world rules so that we can understand it. 

This is probably my most evident &amp; constant BPD symptom. Every single day, the way I experience the world changes entirely. I feel zero connection with my past self. In some ways it doesn't even seem like the same consciousness. It's like I'm a newborn every day.