My first thought was that my worst critic is myself. It strikes me that Seth’s comments apply equally to the me-voice in my head. Criticising myself is literally zero-effort; Much easier even than someone posting a critical comment somewhere.
I’ve never been much for cheesy self-affirmations. (“I’m good enough, I’m smart enough, and doggone it, people like me.”) But I suspect weighting my self-criticism more in line with the effort required to make it would be useful.