Social psychologists have a saying: “bad is stronger than good.”

If you’ve ever noticed that negative experiences seem to be more memorable, it’s not just you—psychologist Roy Baumeister and colleagues pointed out in a landmark 2001 paper that in nearly all corners of psychology, bad events are more impactful than good ones.

  • Losing $100 is more painful than finding $100 is pleasurable.
  • A fight with your partner damages the relationship more than a date night nurtures it.
  • Bad parenting does more harm than good parenting does good.

It’s a fundamental principle of psychology, and a grim one. But knowing about it allows us to compensate by consciously savoring positive experiences. And here’s one little way to do that:

Save any thank-you notes you receive.

Instead of reading and discarding, stash thank-you emails in a special folder and start a manila folder for hand-written notes. In doing so, you create a valuable resource you can tap when you’re just not feeling that great about yourself. Our lives have plenty of dark days, and saving thank-you notes is an easy way to shed a little light when you need it most.

And sending a thank-you note does that, too.