Beware the cute, hot guy who kind of reminds you of the parent you don't get along with: your cold, distant father who left when you were a kid or your hot-tempered mother whom you could never please.
More than any other personality trait, my mother seemed to be ruled by anger and sadness. She seemed to hate being a mother. Watching her unhappiness as I grew up made me conclude that the answer was to try and be as unemotional as I could, which many therapists have taught me is a bad idea. It also made me want to avoid marriage and having children.
Conversely, beware the man who does nothing but ask you questions about yourself and offers no information about himself. Not only is he keeping you at bay, he is probably not listening to your answers.