So first sentence goes against the title, then again, the title is more catchy and broader than "how to find swears in git commit messages".
"I thought about checking on GitHub for which projects contain the "angriest" developers."
I don't know if it just me, but I wouldn't say that the person with the most swears in the commit messages are the angriest, but the least professional.
Is it hurried, written in poor style or maybe even sadistic :/
Sometimes the comments yield clues to that. Best one I ever saw:
# !!!XXX WTF
However, if poor style were the best emotional indicator, I think the angriest developers are all coming from oDesk.