IMO, it's not something that matters. It's just words. There's a difference in using coarse language around someone, and using it AT someone. And even if it's TO them, there's still a huge difference in "Hahaha, what the fuck dude?" and "What the FUCK!?" ya know? Context. Time and a place for things. As long as kids know that it's inappropriate to say things you'd say at home with your family around other people, and in public, where people could be offended, then who gives a fuck. Just don't be rudely offending people, and it'll be aiight.