My SIL, a 6th grade teacher was raised on a dairy farm and to the best of my knowledge has never met a stranger. I marvel that he can meet someone for the first time and engage him in just about any subject.  Also, when we go out for a meal, it sure looks good to see the large number of young men and women that comes up to talk to him and my daughter (5th grade teacher). They are always introduced as their former students.