There are certain words that can only be used by you if they describe you. If they don't describe you, then their use is considered inappropriate
, politically incorrect
or downright offensive
Usually they are used to describe social groups of one kind or another. For example, if a suit calls a geek a geek, then this is considered offensive. But if a geek calls a geek a geek, then this is considered to be not only polite, but almost a term of endearment.
There are many words like this, including: nigger, geek, nerd, wog, chink.