Bob was working the other night, and he saw a customer walking around, and she had her back turned toward him. He couldn't help admiring her ass, as it (and her perfectly proportioned backside) were turned toward him. His thoughts went something along the lines of "Hey baby! I wouldn't mind having you in bed at all." Right in mid thought she turned around, and Bob got to see her face. His next thought: "Ew! I wasn't thinking that about her, I would never even contemplate having sex with her!"
Bob just hates that, when a female has a delicious looking body: nice ass, nice proportions, even nice boobs, nice hair... but has a face that looks like the ass of a cow taking a shit. He especially hates it when he was admiring the girl's qualities prior to seeing her face. For Bob, a girl's sexiness is totally destroyed if she has a gut-wrenchingly ugly face.
Bob probably wouldn't be too choosy if he was looking for a girl to date, as long as she had an amazing personality and is somewhat attractive. A flat chest? He could live with that, no problem. But a butt ugly face? That totally ruins it for him!
I had been pretty quiet throughout the whole thing, but I had to chip in my two cents worth: that she really couldn't help that she had an ugly face, and that the rest of her was still pretty; but Bob arrived at the wrong conclusion. He concluded that this is what the doggy position was invented for.