If you're over twenty, chances are that your little quirks will stay with you forever. Some quirks, I can take (but the assortment is sparse).
I prefer strong characters with a broad life experience, who have been subjected to a cornucopia of adversity, but have nevertheless managed to thrive in spite of it.
What I don't want:
Passive socialites
Aimless small talk afficionados
Facebook/Twitter/texting addicts
Out-of-shape-''I-have-a-chronic-headache'' types
Shopping mall triathletes (Eat/Shop/Sleep, or any combination thereof)
Various displays (too numerous to mention) of insecure, manipulative (female dog)-ing.