I obsess about interpersonal insecurities. If someone I care about seems distant or doesn't call me back once, I think - "oh, no, they've discovered that I'm weird and no good and now it's all over". I will keep thinking about these ideas fretfully, mulling over what I may have done and why they don't care for me. I will do this until I have some sort of attention from them and confirmation that things are fine. If someone makes fun of me or declines an invitation/reaching out on my part, I begin to think repeatedly that they must have discovered that I'm a weird, messed up person. I begin to think about everything that I could change about myself to be normal, or to be accepted by other people. These internal sessions can last for days on end. It's like one big endless self criticism and self improvement bandwagon. Other than reinforcement from other people, my only way out of this state is immersing myself in excercise or drawing. They help me to lose track of my ego and these destructive thoughts.