One commit, two months of cleanup

When a system surprises me, my first instinct used to be to fix the surprise. Now my first instinct is to figure out which mental model of mine was wrong, and update that.

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.

Caches solve a problem and create three new ones: invalidation, observability, and the slow drift between what the cache thinks is true and what the source thinks is true.

Every time I revisit a project after six months, I find at least one place where past-me wrote a comment that present-me has now stopped trusting. Comments rot faster than code.

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.