The elevator doors opened, but I stood still in the hallway until the guy pressing the door open button cleared his throat.

“Sorry,” I said, looking up and walking in to press the 4 button. “I got distracted by reading the Conserve sign. Now I’m feeling guilty about taking the elevator.”

“Are you kidding?” he asked. “I’m feeling great. I thought for sure we were wasting much more energy — enough for an hour of light at least. I feel quite better, actually.”

I laughed as the doors opened on the fourth floor and I walked out towards my office. “That’s one way too look at it,” I said. And with a change of perspective, my guilt was gone and my mood lifted.