Rebellious: Pointless as an adult.
Coward: The constant fainting.
Absent Minded: It's a chore to get a sim with this trait to do anything. And I like my sims to be self-sufficient.
Loser/Unlucky: Does it really need an explanation?
Light Sleeper: Sleeping through the night is hard, I would know.
Dislikes Children: All of my sims are Family Oriented.
Slob: Makes a mess every time! But it makes the maid earn her pay.
There's more, but I'll stop my rant there. What's the point of these bad traits anyway? Didn't EA understand that they'd be rarely used?