I achieved good calibration by paying attention to evidence and avoiding known biases as well as I was able. Once I had established reliable calibration, I experienced temptation to justify my first intuitive instinct by asserting my own calibration.

My calibration was based upon mediating my intuitions with reason. I can't invoke it to trust any old estimate that comes out of my mouth: if I did then I could say whatever I want and trust it to be calibrated (which would yield probability estimates out of touch with reality). Hence the parallels to Löb's theorem.