Have you ever used git bisect? If so, how did you use it? Did it help you find a problem which would otherwise be difficult to find? Story time, I guess?
git bisect is probably one of the most revolutionary parts of git, you can even automatize regression testing with it (if you have a regression test, you can run git bisect script.sh and it will bisect automatically the problem for you). I have used it lately to automate performance testing & regression finding.