A loss can remove illusions that success would have preserved.

Success is a poor auditor. It lets bad assumptions, weak processes, and lucky breaks survive undetected, because nothing forces you to look. Loss removes that protection and shows you which parts were actually load-bearing, which is unpleasant and genuinely valuable.

After something fails, ask what you had been believing that turned out not to be true. Note it plainly. The illusions that go first are usually the ones that would have cost the most later.