The Code Review Comment I Left 47 Times

The Code Review Comment I Left 47 Times I counted once. Not proud of it. Forty-seven times across different PRs, different engineers, different companies — I left some version of the same comment. It usually looked like this: "Hey — this nested loop is going to hurt you at scale. You're doing O(n²) work here. Can you use a set for the inner lookup instead?" Sometimes the author got it immediately and fixed it in ten minutes. Sometimes I'd spend forty-five minutes in a thread explaining what O(n²