Disturbing Discovery

I spotted an old friend while driving home in the bus this afternoon.
I could see him looking at me thinking " Is that. . .Rosa? I think. . . maybe. . ."
I waved vigorously and smiled broadly when he realized that yes, it was Rosa!

 I made quite a disturbing discovery during this incident however.
While my hand was waving vigorously,  my underarm was jiggling just as vigorously!!!
Sigh. . .
Middle age.
The age of disturbing discoveries.