The Parker Walk
If movies are a window into the time when they are made, then it's pretty clear that the "Parker Walk" is THE original social dance. Danced more often by more people than Swing, Ballroom and "Steppin'" put together.
At some point in history this might have been called the original "two-step". This was what my generation (at least in South Central LA where I grew up) called "slow dancing". At any rate, this is my favorite dance to dance. When someone at the ballroom asks me what are we doing, I used to say "free styling". Now I say "Parker Walk". What the heck?