Mrs. G. sent this one to me under the lovely heading, "Peer-reviewed gruntle!"
A study by R.A. Emmons and M.E. McCullough in the Journal of Personality and Social Psychology found that people are happier when they articulate each day what they are grateful for. In an experiment, both psychology students (reasonably healthy) and neuromuscular disease patients (with something serious to be unhappy about) were asked to write down each day a list of things they were grateful for. After two or three weeks, both groups were happier.