actually happened

Walk out of house with adolescent son right behind me.  I have bag in hand which I'm going to put in trash at side of house.  As I walk down the front stairs to sidewalk, three young girls say hi to me (or at least the eldest of the three does, because the other two are very young).  So, I say hi very pleasantly because I know the older sister of the one who said hi , G.;  she is in school with my son.
I take the trash and come out and see my son in this stiff - really uncomfortable looking - pose.  Somehow I know that it has something to do with the girls.  I say, "Did you say hi?"  He said, "No, I don't even know G.'s sister."
In other words, even though it was clear who these girls were (family resemblance if nothing else) and even though they had said hi first, he didn't feel as though he should say hi??? I can only conclude that it is adolescence which causes him to seem silly in his quest to avoid appearing silly.
Oh well, life is hard for those of us with poor social skills and enough insight to realize that they're poor.