power napping is napping with the full intent of only being asleep long enough to rejuvenate your "livelyhood". In other words, sleeping long enough to wake you up. As we know, during sleep most of your bodily systems shut down temporarily due to not being used. According to some doctors (ones I've asked about it) power-napping causes those systems to shut down even though you don't have the intent of staying asleep long enough to need them to. Which confuses them and could possibly cause them to not function properly upon your waking.
"Applause begets applause in the theatre, as laughter begets laughter and tears beget tears."
CLAYTON HAMILTON, "Theory of the Theatre"
"I think theater ought to be theatrical ... you know, shuffling the pack in different ways so that it's -- there's always some kind of ambush involved in the experience. You're being ambushed by an unexpected word, or by an elephant falling out of the cupboard, whatever it is."
TOM STOPPARD