ditto..I am the same way,I make friends differently then most.First I will subtly reject them ,test their boundaries,watch their responses and gauge how they act/react to me..in the end I decide either or not they are worth the time to get to know.
In a world where everyone where everyone wears their heart on their shoulders and give/expect approval immediately,it's often interesting to see how they respond to tension/lack of immediate gratification of approval.
Living by the statement,the hardest people to get know are usually worth the effort in the end.And the people that are the hardest to love need it the most...
(: