I never liked team sports. I just don't get them. I don't get any enjoyment from being a part in an apparatus, such as a lineman or an outfielder. That's one reason.
Of course we'll all say we play because we enjoy it. At least I hope so. But why do we enjoy it? I enjoy it because it's a challenge, and it's so intensely physical. I'm an editor and a writer. I sit in a desk all day and most nights, working with words and ideas, abstractions, symbols. The rules of grammar and style are complex and amorphous. Tennis however, is tactile, sensory, and straightforward. There's boundaries. It's cut and dry. It's either in or out. You either won the point or lost it. Plus, I'm out of my seat. I'm running. Thinking only does me so much good. Mostly it's physical, about guts and patience, endurance -- with some smarts of course. To be honest, I don't enjoy the competition that much, in part because I'm not a great competitor. Competition stresses me. But that's okay. Over the years, I have learned that I don't need to be a great match player to enjoy the game. Maybe like Santoro versus Federrer that way.
Finally, no matter what my troubles, tennis takes my mind off. Unless I play really bad, which is quite often. But even then, adrenaline eases the pain. And that night, when I go to sleep, I can replay the fun points and winners I hit in my mind until I fall asleep.