While cursing in your git commit messages probably doesn't correlate to actual anger at your company, here is a quick an easy command to look for curses in your project git logs. (Based on this gist)
From inside your git repository
$ git log --pretty=format:'%s' | tr '[:upper:]' '[:lower:]' | tr '[:space:]' '\n' | sort | uniq -c | sort -nr | grep -iE "(fuck|shit|bitch|damn|piss)"
Looking at my last company's repository, it seems like there was a lot of anger.
18 fuck 7 bullshit 6 shit 4 damn 2 fuckin 1 shitty 1 shit, 1 fuckkkkkkkk 1 fuck'
I thought about checking on GitHub for which projects contain the "angriest" developers. However after spot checking a few of the top projects (bootstrap, coffescript) there wasn't a single swear in their logs. Apparently these projects are a bit more professional than my last gig. Another roadblock was that I was unable to find a way to programmatically pull the most popular projects from GitHub without writing a full blown scraper of their popular projects page. ) I did figure out how to pull down the commits for a repository though in case anyone is interested.
Pull down commits for a project using the GitHub API.
$ curl -u '<github-username>' https://api.github.com/repos/mbostock/d3/commits