Bad hygeine, serious alcoholics, and smokers. I guess depending on how well the connection is I can MAYBE overlook smoking, but it has to be ONE HELL OF a connection to rule all loves, and when they smoke they better do it outside and away from me......and keep their breath fresh all the time. Being controlling or nagging or being a big worrier. I already have a mother lol

Cigarette smoking, having or wanting children, actively disliking Doctor Who (mainly because it's absolutely everywhere in my home and they'd be miserable/infuriated/etc), not being at least somewhat active.

Lacking a genuine love for truth, in the scientist-at-heart kind of way, is a deal breaker.

Smoking tobacco. Just can't deal with the smell.

Bad teeth