Vampire!

I've put together a handy guide to help you identify vampires, using my knowledge of L. J. Smith books and vague memories of reading Anne Rice's Vampire Chronicles. If you know someone who's displaying any of these symptoms just stop being friends with them, unless you want to be drawn into a world of intense brooding and self-importance.

Symptom #1: DOESN'T POO
That's right, vampires have no need to go to the toilet. In The Tale of the Body Thief, vamp-sex-pest Lestat swaps bodies with a normal human and practically the first thing he does is take a huge, minutely described crap.

A Further Sign: HAS RETURNED TO HIGH SCHOOL
If they're able to go out in the daytime the first thing vampires do upon arriving in a new own is enroll in high school. Ostensibly so that their vampire nest/coven can pose as a normal family, like in Twilight. Another reason is of course to bag a teen companion. Teenagers are young and largely unaware of, or at least unconcerned by, their mortality. They are thrilled rather than terrified by the threats posed by vampires:
-Chasing
-Hypnotism
-Biting
-Goring
-Wrinkles induced by extreme brow furrowing, see Vampire Diaries:

Speaking of Nests: HAS GROSS WHITE-TRASH POSSE
I'm mostly thinking of the crews of grubby, unkempt undead in Near Dark and The Lost Boys. Near Dark was the worst though, "If you wanna be part of this group you gotta blah blah blah blah"

I understand the need to connect with people who are like you in some way, it's just too bad for vampires that most of their kind are mental or wankers or an adult trapped in the body of a child. Is adult the word if you're 100+? Is there something beyond adult? Elderly? Meta-old?

Weird but True: FEAR OF DAVE GROHL
Especially if he's sans beard, see below:

I dunno, maybe he's some kind of paragon of virtue or maybe he's a vampire hunter and shaves when it's hunting season to make himself more aerodynamic.

Also: LOOKS LIKE DATA
Looking like a character from Star Trek: The Next Generation is quite common in the Twilight films, but the best example is 1920s Bill Compton from True Blood:

In Local News: SPATE OF ANIMAL ATTACKS
No it's not your vampire friend, it's the werewolves that inevitably follow a discovery of vampires. Do you know anyone who seems like they're on steroids if there's a full moon? Werewolf. See Tyler Lockwood/Smallwood of Vampire Diaries:

That's everything I can think off of the top of my head, especially now that I've brought up werewolves and can't concentrate on anything until I have obtained this book from my childhood:

Where a girl knows she is becoming a werewolf because she starts absent-mindedly eating raw meat while chatting with her mum in the kitchen.