Article: Why Do We Say That?

The origin of "On the wagon" derived from the days in which dynamite was transported in horse drawn wagons. If you were driving the wagon the next day you could not have whisky the night before because you were on the wagon the next day.

Jim Mize
DeLand, Florida

I had no idea about being on the wagon. Shaking hands evolved from ancient times when two strangers would meet and check each other's sleeve for a knife. Women were not considered a threat. Thus it became a custom for a man not to offer to shake a woman's hand unless she extended it.