"Systems fail at the boundaries between responsibilities.
The quote is short, but the word responsibilities carries the weight. In a scaling issue where efficiency and resilience pull apart, it tells you where reality will push back, even when the plan looks clean.
In a scaling issue where efficiency and resilience pull apart, good engineers will do what the system rewards. You see it in a boundary shift that moves work onto a team that did not agree, and you can’t fix it with reminders. Make the signal observable, not philosophical, so you can act without debating intentions. The system learns from what you allow under pressure, not from what you say you value in calm weeks.
Diane Vaughan is a reminder to keep it concrete. Put the assumption into words, then choose the signal that forces you to revisit it. Be calm and explicit.