If you—without tongue in cheek—find yourself explaining the proper usage of “dork”, “geek”, and “nerd”; then <foxworthy>you just might be</foxworthy>...whichever one you think is worst. If you’re (again, without tongue in cheek) offended by someone’s usage of one of those terms, then you are.
(Ah...the sweet irony of hyperlinking those words to Wiktionary.)
Incidentally, no matter how inaccurate it may be, I like the pop-etymology: drunk → knurd → nerd.
And as Scott Meyers wrote: “Jocks are just sports geeks. Live with it.”