I tend to stay on the phone because I want to be sure that whoever I'm talking to has said everything they want to say. This is typically the case with IN** friends. There's usually a point where we'll just run out of things to say and just sit there quietly for a few seconds and eventually one of us says "Yyyyyup, well..." and that's kind of like "the signal". I don't really have a problem ending calls with other personality types though.