How do you push people away from you when you feel they are getting too close?
If you actually like him/her and you tell them that you consider them a friend, do you then just put zero effort into the friendship, until your "friend" finally goes away, out of your life?
If your friend stays because he/she believes that you may eventually let them in, what then, do you resort to being mean to them so that they finally have no choice but to leave you alone?