You don't have to talk like an illiterate, rebellious teenager to be your own person.
@Hashbrowns Not only do I strongly agree with everything Stephen Fry has already brought up, but it's absolutely ludicrous, in a pretty quantifiable way, to claim that the use of additional words constitutes a smaller vocabulary. You do know that a vocabulary is the range of words at ones disposal, don't you?
If you think that limiting your, yes, vocabulary according to arbitrary standards of which synonym of a word is the naughty one, then you're being extremely simple.
On a more personal note, I find that the occasional expletive adds a nice bit of texture to conversation, personally. Cuss on, gentlemen!