I noticed yesterday evening a significant number of homes with outdoor Christmas lights still up and shining, far more than I remember in past years by mid-January. (No data here, just a hunch.)

They looked like the new high-efficiency LED lights, which seems to be the Jevons paradox in action. The core of the paradox is that, as energy efficiency improves, rather than simply using less energy we often use more of the good the energy provides. In this case, it’s joy. Lights left up for extra weeks after Christmas gives me extra happiness.