Dance like nobody's watching…unless someone IS watching.

I've watched this video five times.  No, I'm not trying to learn this guy's smooth dance moves.  I'm trying to figure out what is the best ingredient of this viral video.

Is it that he's dancing to "Morning Train" by Sheena Easton?  Is it that he REALLY enjoys cleaning in his underwear?  Maybe it's the embarrassed look on his face when he realizes he's dancing like nobody's watching...while someone is watching...and filming.