It feels very tied to my sense of worth. As a child I was only valued for my "smarts" and I knew that this was conditional. My greatest fear was brain injury because I felt completely sure that I would no longer be valued by anyone. Later I think this morphed into a kind of emotional/intuitional "smarts" where I felt people valued me because I was good at making them feel safe and supported and understood, and if I fucked up at that, I would no longer be valued. This was affirmed by being abandoned at my first failure (that I was made aware of) several times. I think it was also compounded by living for 8 months with someone who expected me to read their mind and do what they wanted without them telling me, and when I failed I was treated with hostility and ostracized from all human contact (they had this power because my only friend was hours away). And then I was in a relationship for many years with someone who would radiate their stress and anger at me unless I figured out the source and helped them feel better about it somehow.
When I cannot understand, cannot show support in a way the person wants, or cannot give safe space, I feel that I am on the verge of true worthlessness, and my entire life depends on them forgiving me for fucking up and trusting my history of success enough to let me try again. It's not a logical thought progression but it feels unbearably real. When it happens with someone I like, it hurts for a little while: when it happens with someone I love, I can think of nothing else until I am forgiven or am certain that I have no chance of forgiveness.
With people I choose to have in my life, I always assume that they are doing their best, unless/until they tell me they do not want to try. I can't bear the idea of not affirming someone's best efforts. I can't bear the idea of someone offering up their best, and someone else not giving honor to that. I can't stand 'art critique' for this reason. The only person who can know if the artist didn't do their best is the artist themselves! And the only way for art to be bad is for the artist to not give full effort. It cannot be judged from the outside.
If I call you a friend, please always assume I am doing my best to offer understanding, support, and safety. If you doubt, ask if it is my best. If I could do better, tell me how. If you cannot start with the base assumption that I am doing my best with what I have, do not be friends with me. I need that assumption in all my friendships.