His hair looks like it smells like a frat house couch
It's greasy, it's generally unkempt, and mostly slicked back with some kind of sticky substance. Also, it smells like pot, cigarettes, and booze. Basically, you'd be doing the dirty on - or worse, with - the old frat house sofa. Gross.
Alcohol has given him major face bloat
He's still cute, but we're not talking Legends of the Fall cute, anymore. If rumors of alcohol abuse are as true - and as rampant - as Jolie persists, Brad's got some serious alcohol bloat going on, and what's scarier than wobby man jowls hovering over your face intently?
When he's got a beard, IT'S A BEARD
Beards are fun, beards are great, beards like Brad's kill your ovulate. No, but really, there's well-groomed, and then there's flavor-savers. Anywhere in between is fine, but when he grows that goatee (or is that the entire goat?), the last thing we want to be thinking about is intercourse.
His mouth probably tastes like an ashtray
... Or a chimney. Whichever you prefer. And when you mix coffee and cigarettes, it's a double-whammy. Trust us. It's mega gross, unless you're a coffee-drinking smoker, and then this one probably doesn't apply to you anyway.
He slept with Jennifer Aniston
... And don't you know, it's not the cooties that are catching, it's the crazy. And Aniston is the cream of the crazy crop, and do you really want to go there?
Gwyneth Paltrow probably put a hex on his dong
Being as GOOPy as she is, Gwyneth Paltrow - who once said that Brad was "too good" for her - probably put some kind of magic spell on Brad where his penis consciously uncouples from the rest of his body, thusly making the encounter an astral experience. Or in GOOP's case, ASStral.