User names with more than one extra "X":
Okay, these names were unique when they were first spawned from some Goth kid's head, but X's don't make your user name look cool any more. It makes you look like some emo/goth wannabe who is just looking for attention.
User names with random numbers on the end:
When you type in a desired user name but it's already taken, the computer makes names as suggestions, like instead of JohnSmith, you're J.smith, SmithJohn, Johsmi, JohnSmith233... etc. The list can go on. Just because you want your "desired" user name, doesn't mean you need to memorize pi.
User names that are just misspelled words:
Misspelling used to be cool, now it's not. Nobody cares if you type "da" instead of "the" or use extra letters. If the best thing you can come up with for your user name is a word, then you really need a thesaurus, or maybe a brain. The only thing that using a misspelled word as your user name shows is you have no imagination, and no idea how to spell.
User names which are celebrity names:
Sure, we know you love Lady Gaga. Definitely, Elivs was the king, but do you need to dedicate your whole entire account to them? Just because some celebrity has caught your attention doesn't mean you need to name yourselves after them. It'd be pathetic if later on they were just a trend, and you were stuck with a crappy name. So leave Michael-Jackson-is-Christ to the actual Jackson family, and come up with your own names.
User names with random capitalization:
SuRe, WhO dOeSnT lOvE rEaDiNg wOrDs ThAt lOoK LiKe A mOuNtAiN rAnGe? i KnOw ThAt yOu hAve tHe RiGhT tO tYpE LiKe A mOrOn, bUt DoNt sUbJeCt OtHeRs tO iT.
User names that try and cram a whole sentence into one word:
Usually, any site that wants you to create a user name gives you at least 9000 options to express yourself, whether it be in comments/blogs/journals/ID's/smoke signals, etc.. So why must you express it in a user name? Nobody judges you based on your user name alone, stop trying to cram an entire biography into it.
User names that can worry people:
Sure, they sound mysterious and deep to you, but to others it sounds like you need a psychiatrist. If anything, some medication. Unless you really DO need help, stop making these names. You're the person giving everybody else gray hairs.
User names in all caps:
HI, BILLY MAYS HERE WITH MY NEW MYSPACE ACCOUNT. STEPHEN HAD TO GO TO THE BATHROOM, SO I'M DOING THIS ONE. YOU TIRED OF LOOKING LIKE A YOUNG PERSON? WANT THAT "I JUST FOUND OUT WHAT A COMPUTER IS" PERSONA? LOOK NO FURTHER THAN THE ALL CAPITALS NAME. OR MAYBE YOU JUST LIKE SHOUTING. NO PROBLEM! ORDER NOW FOR 19.95, AND WE'LL THROW IN "LOOKING KINDA STRANGE" FOR FREE! DON'T BELIEVE ME? LOOK AT THESE MAGNIFICENT EXAMPLES!