You never run a git blame or git bisect to find out when and under which circumstances a regression or bug was introduced, and why this specific change was made? That might work for a while on a personal project, but is essential in a team project. It's not uncommon that by fixing a bug you also accidentially undo an actually intended change. Doing some software archeology in the git history and tracing back the steps that led to the bug/regression usually prevents that sort of thing. You'd also want to notify the person who introduced the bug (and if this is a good and honorable chap, they'll fix the bug themselves).