This is one of my most random ever analogies but it does work, bear with me. So I breed Shetland Ponies, most of them are really lovely and friendly but one of them, Mayfair, isn't. In fact she is moody and flighty and generally just not as nice as the others, except to me. She loves me and for some reason that makes her my favourite too, because she only tolerates other people! I do love all my pets and ponies but Mayfair has a special spot, partly because she was also my first pony.
However, I feel that that doesn't work with humans. I wouldn't want to date someone who snaps at other people, is rude to them, or disrespects my parents. It doesn't matter if he's a sweet cupcake to me, if he's going to treat other people that I know badly, I want nothing to do with him.
I also wouldn't really want a dog/pet like that, either. It made me feel special then, but I like owning pets that like people.