I've heard many times that cats (and perhaps other pets, though I can't stand dogs) have the ability to relieve or reduce stress in people's lives.  I think I know why:  Cats are easy to please and amuse, and they always show you they like you (as long as you're nice and you feed them regularly).  When you pet a cat, it "smiles" and purrs to let you know that it's happy.  Unlike a human, it won't reach an age where being pet becomes "weird".  It won't want to spend more time with its friends or feel like you're too bossy.  Cats don't become much more mature than when you first get them.  They appreciate what you do for them and they show it.  I think the appreciation they show and the ways they show you they like you are an immediate reward for a service you're performing.  They don't ask for anything in return.  They don't dump all their problems on you.  They don't tell all your secrets to your neighbors.  You pet them; they like you.  So simple. #nature