Customers that curse at McDonald's

[XCashier]

For that matter, if an employee has friends come in to their workplace, and the friends start speaking to the employee using foul language, should the employee be reprimanded for joining in or for not telling the friends to tone it down?

Joining in, yes. Not telling the friends off, well, the employee might not be brave enough to say, "Guys, cool it, I'm on the clock." The manager would be quite within rights to step in at this point.

The employee in the OP should not have been yelling the n-word and the f-word loud enough for the entire store to hear. Like the old saying goes, "Profanity is the effort of a feeble mind to express itself forcefully." Yelling a profanity because some hot grease splashed on your arm might be understandable, but in common conversation, like in the original post, it's really not necessary.

[Dreamstalker]

I think that the kids feel all grown up when they talk like that out in public.

That's what I've always thought too. Sometimes I'll hear some obnoxious little tweens on the T swearing up a storm; it seems I can tell that they think it makes them "cool". Same with the wannabes (wiggers etc). You don't sound cool, you sound like a poser and an ass.

I'm of the mindset that no matter what the job, you should avoid swearing in earshot of customers (especially if there are little kids around, as we all know how some kidlets love to parrot anything they hear) if at all possible seeing as one of the too-easily-offended crowd may decide to complain and blow things out of proportion.