Open this photo in gallery: Serbia's Novak Djokovic in action against Italy's Jannik Sinner during their men's singles semifinal match on day twelve of the Wimbledon tennis championships in London, on July 14.Alberto Pezzali/The Associated Press In an effort to establish whether indulging our pastimes make us healthier, a bunch of social scientists first had to define what constitutes a pleasurable pursuit. They came up with a tool called the Pittsburgh Enjoyable Activities Test (PEAT). The PEAT breaks enjoyment down into 10 broad categories – things such as ‘being in outdoor settings’, ‘involvement in hobbies’ and ‘doing fun things with...