I've run over 100 post-mortems. The worst ones end with 'Alice will be more careful.' The best ones end with 'we fixed the system.' Here's how you get from the first to the second. The language rule Ban these phrases from retros: 'Should have...' 'Alice forgot to...' 'If only...' Replace with: 'The system let this happen because...' 'The runbook didn't cover...' 'The signal was missing...' People make mistakes. Systems that allow those mistakes to reac...