A few years back I worked in a university building that also housed an entire department full of psychologists, all of whom seemed to see us administrative types as perfect guinea pigs for their latest theories. I learned to be wary of answering seemingly casual questions in the elevator. If an eager graduate student showed up in my office bearing a tray of pastries and asked me to pick one, I'd cast a chary glance and ask "Why?" before grabbing the apple fritter.
So one day, when someone from the Psychology Department posted instructions in the bathroom exhorting all of us to "Think about five things for which you're grateful every day for a week!" my response was frankly suspicious. I did the math. Five things a day for seven days is a lot of brainpower to expend without so much as the promise of an apple fritter.