I work in an office where there are 4 of us in the corners of a cube. One of the guys who sits in an adjacent corner acts a little strange. A few times a day (or more), he curses under his breath as he's working. They're just little things, along the lines of "Why does it [insert expletive]ing do that?" or "Such a [insert expletive] piece of [insert expletive]." It goes on for 15-20 minutes at a time.
Don't get me wrong--I'm sure plenty of people (including myself) think these things from time to time. The business of software development can be a real [insert expletive] sometimes, and I don't fault him for feeling frustration. It's the audible venting that I find strange.
Normally I'll put on my headphones during these quiet outbursts and ignore them, but recently I've been more worried as they're sounding more and more angry. I know I'm not the only one who hears it; the guy over the cube wall will jokingly remark "Tell me about it, [coworker's name]!" from time to time. My coworker seems to come out of his programming trance and laugh it off, but it hasn't changed his behavior long-term.
Is this something that isn't my business (it's not preventing me from getting my tasks done) or something I should bring up to him or someone else?
EDIT: Wow, didn't think I'd get so much feedback--thanks, everyone. Part of what made the behavior so weird to me is that no one else in my office does this. HOWEVER, I'm very glad to hear that this is by no means a strange occurrence in the world of software development (or offices in general). I appreciate the perspective.