I worked with this guy at a startup one time, and just to annoy me, he would write commit comments describing how I was such a bad developer, or how I was such a horrible person. After like the 15th time he did this, I decided to be totally unprofessional and do the same for him... our commit comments quickly turned into a conversation where we would just insult each other (as a joke).

The original developers of the startup no longer work there (including me and him)... I wonder who's reading those comments now.