Sure, there are a million reasons that old European cities lend themselves to bike commuting better than many in the U.S. American infrastructure is designed mostly with the car in mind and many people live far from work.
But still, just imagine. No hour in gridlock. No honking and road rage. Maybe the occasional bike accident, but mostly fresh air on the face and a nice sweat worked up on the way to the office.
It also looks like bikers in Copenhagen know how to respect traffic laws. Hint hint.