Something Has Been Bugging Me

I've been wondering....How many of you have asked someone to add you to their friends list only to be denied? What reason could a person have for not giving someone the opportunity to gain a new friend? There is a painting of a wall with two figures in it. One of them is leaning over the wall with his hand outstretched. You only see the arm of the other person reaching up as if needing help. In my mind I have this image when I make a friend request. When I don't get a response, I see the outstretched hand being slapped. Is it just me? It couldn't be personal since the person doesn't know anything about you except for what you have written on your profile? Or could it?