There are lots of things that the good dancer does that are seemingly unknown or totally unimaginable to many twirl and barf dancers. Good dancers fit their movement to the phrase of the music. Most contra dancers dance at one speed and are thus often guilty of finishing a figure too early. The beginners did fine, the experienced contra dancers didn't listen.
Good dancers embellish appropriately.
I'll bet many people who think of themselves as good dancers couldn't get through a dance without all the extra twirls. They don't know what the basic movement is or what it feels like. If you don't understand that, the embellishments lose some of their character, and even their potency. Embellishments and flourishes work when they come at the right time in the right situation with the right people. They should not be automatic.