If you want to flesh out a character's personality, pick a deity for him to worship and give him the associated religion trait. Abadar is one of my favorites, and Eyes and Ears of the City is a pretty good trait if you're not taking Reactionary.
If you just can't see your character as having any love for a Lawful deity, then Fortified Drinker is kind of funny on the other side of the coin, as long as you're willing to constantly carry a flask and convince your GM that yes, it's been less than an hour since your last gulp. I think if I were the GM, I'd want that player to start tracking his liquor budget though.
Dirty Fighter is a pretty nice trait for a rogue, or for any melee who's in a party with a rogue. It also mentions a childhood friend, which means you have to actually decide who it was, therefore opening up roleplay opportunity.