Comment Language/cultural barriers (Score 2) 473
I'm surprised nobody's mentioned this. I work on a project that's spread across eight countries. The lingua franca is English, which makes me one of the lucky ones as a native English speaker. As you might guess, it's a pretty big project, so things like push-button refactoring aren't any use when someone misspells a variable name, or inadvertently names something after a swear word or a racial slur. (Or, more to the point, did so in acquired code that's now 12 years old and really shouldn't be touched if it's been working fine, and there's no staff for cosmetic changes anyway.)
People have talked about commenting and documentation. It's that much worse when someone's writing in their third language, or they write in their native language and you hope you can translate it well enough to get what they're really trying to say.
And then you've got all the cultural issues surrounding hierarchy, face and the loss thereof, egos, power, seniority, communication formats, and all that.
I'd love to have the luxury of being the lone cowboy, even if the PHBs were constantly jerking me around about what I'm supposed to be doing.