Live vs Online Chess

I have started playing short games in "Live Chess" here at chess.com and I am finding that my rating tends to be 200-300 points higher than my online chess rating.  Are other people finding the same thing?  Am I good at blitz games because of some supernatural ability to think on my feet ... or am I just impatient and thus bad at online chess? 

Feel free to add this to your list of unanswerable questions.