Dear Abby might say that if you want to observe a potential mate's true nature and temperament, meet her/his mother and see how the two interact. How does he treat her? How does she respond?
Sometimes, though, it's not practical to meet mom, or maybe it's too early in the relationship. In those cases, I suggest this runner-up of assessment tools.
Play a few games of miniature golf.
I saw Daughter Number Three-Point-One behave similarly at a much younger age, as well as a niece when she was about five.
What does your guy do when he blows a shot? Where does the blame lie? What's your gal's overall attitude -- is she playing for fun or as a serious competition? And if he's good at the game and wins easily, what kind of winner is he?
Take DN3.1's father, for instance. He's probably less athletically inclined than any man I know, but he usually wins at mini-golf. Despite this, he never lords it over anyone; he takes a kind of technocratic pleasure in figuring out the angles and strategies of playing each hole.
I, on the other hand, can be petulant when it doesn't go well. It's not as though I consciously believe the competition is important, but I can't help being annoyed if I blow a shot or the ball just doesn't go in the hole when it could have.
And I would say those two descriptions fit our temperaments pretty well: He is solid and mostly unperturbable and I am, shall we say, less so.
I know this is only anecdotal, but my years on the little links tell me there's something to it. So give it a try, or recommend it to your friends who are part of the dating game.