Things broken on purpose

Most of the trouble I see in production comes from boundary cases someone promised would never happen. The code is fine. The plan is fine. The promise is what ages badly.

The team I learned the most from didn't have great tools. They had a great habit of reading each other's pull requests in full, including the parts that weren't theirs.

The fastest debugging trick I've learned is to write out, in one sentence, what the system is supposed to be doing. Half the time I notice the bug while writing the sentence.

There's a kind of premature optimization that comes from imagining a future team. "What if someone needs to swap this out?" Often, no one does.

Latency budgets work better than latency targets. Targets are aspirational. Budgets force you to delete features when you go over.

Most retry logic I've removed turned out to be hiding a real bug. The retries made the failure invisible, and the bug compounded for months in the background.