Happy Feet!

A misnomer: it's not typically a sign of feeling happy. It's more often an expression of nervous energy to have your feet excitedly moving about. It's happened to me: I've found myself doing a step back/step forward dance while speaking to an audience, but as soon as I'm aware of it, I'll do what I counsel people to do--stop, breathe, proceed.

As I've written before, movement is fine as long as it is purposeful and furthering a narrative. If it isn't, it's something to be addressed. As my great grandfather was fond of saying: "Keep going, be happy!"