“I don’t want to go out with him again.”
“Why not?”
“I don’t know, I just don’t.”
“But he’s such a good, smart boy.”
“He’s annoying. Or boring. Or had a bad tie. I don’t know! He’s just not for me, okay?”
Sometimes, you just know it isn’t going to work. It’s called a gut feeling, and it’s usually right. It might be self-fulfilling-prophesy right, but it’s going to be right, so there’s no point in arguing.
Still, sometimes you need a reason. Either for the pushy parents or shadchan, or for your rational self. Why oh why don’t you want to go out with this lovely boy again?
And sometimes the reason is stupid, because you’re groping. But that doesn’t mean you’re any less right.
Bad for Shidduchim 
Women reject men for trivial reasons;
then the women complain about the man shortage.
I don’t often notice the shoes of men I date, but I once saw a man wearing sandals with socks. Oh, how I wished I could date him!
I wear socks with sandals in the winter, because I hate shoes- they make my feet sweat. I wear sandals with no socks in the summer.
I wear socks with sandals in the summer, but that’s because I’m a super-religious nut. Men with sandals+socks represent the stereotypical chardal beinish- that’s why I love it.