The Rule of Three

I've heard that it takes three dates to know whether a person is someone to continue dating. I'm not sure that I agree with that, but since I've never actually had a "real" third date (not counting relationships that were "relationships" from the beginning because of a pre-existing friendship), I'm willing to test it to a point.

As I said after the lunch date, there was no click with the boy. I'm not the least bit attracted to him. My mother at this point would pipe in and say that my aunt wasn't attracted to my uncle at first...but my mother frequently sticks her nose in where it's not wanted - this is the woman who, in not so many words, told me that I am going to die alone because I'm too picky. So anyway, even though I'm not attracted to him, I've agreed to dinner. Even though there's apparently a "rule of three," there will not be a third date with this boy, unless there's some sudden spark, which I don't expect. I just don't want to have to avoid an unwanted kiss good night, and I definitely don't want to participate.

Am I just too closed-minded about this? Am I supposed to follow the "rule of three" and give this guy (who looks great on paper but just doesn't do it for me) a third date? Help!