It spans the generations, the color wheel, and economic barriers. I’m told in some states you must have it at the wedding for the marriage to be legal. We had it at ours, Wayne just doesn’t remember. Granny does it; the kids do it, although not as well as the able bodied adults, hell even the priest does it if he’s had enough wine. But even so, I was a little surprised to see it done in the middle of the dining room of the Greek restaurant we visited last night.
But perhaps I shouldn't have been; because it also spans the species.