I don't usually say I have a bias, per se, because I appreciate and adore everyone, but sometimes I just have to play favourites. The easiest way to guess my initial bias is by their muscle mass and how cute their face is. Once I actually get into the group, then there's just no telling. Everyone's different. Some are simply more appealing to me than others.
I'm the same with ships. I am super easy with ships. Any ship that sails, I'll join the crew.