SAYING "I DON'T LIKE YOU" NICELY???

Telling someone you don't like them nicely, is there such a thing? Not that I know of. I ask this question because I find myself meeting new people here, and while these people are nice enough, they just aren't people I click with. I don't hate these people at all, they've done nothing bad to me, and they really are good people - I just don't care to hang out with them. So instead of just being able to tell them this, I have reverted to being that stupid teenager girl that keeps avoiding the phone call of that obnoxious ugly boy that keeps calling and calling and calling. Why is there is no polite way to do this? It's so frustrating. Why can't this world be a little less sensitive and just accept that some people just don't like your company? I mean I totally know that everyone in this world doesn't just love me to pieces. (I don't know why... but whatever - ha, ha, ha) So why can't we just say, "Hey your a nice person, but stop calling me because I really don't want to hang out with you" without offending them? So if anyone has some advice on this subject be sure to let me know.