Meeting a new partner, or going on a blind date can be scary because we literally know nothing about this person. What if you say something offensive? What if he likes to jog around Central Park for two hours in the morning, and you recite a dissertation on the love you have for sleeping on your couch during the day in the pajamas your Grandma Mertle gave you?
Or maybe what if he's really sweet at first, then later on down the road (when you've spent lots of time together) something catches you by (unpleasant) surprise?! Even if it does work out, don't you just want to know ahead of time?