Why do we find it necessary to joke around with the people we are comfortable with?

Ok i was contemplating this; Why do we find it necessary to joke around and give the people we love and care about “a hard time” ? This might be a little difficult to understand i’m not sure. But i know personally that once i have accepted someone as a friend that i feel almost compelled to give them hell sometimes when i’m around them. Any ideas on this? Or is there some psychological theory as to why we do this?