Golf & Tennis are for folks with money. You almost have to spend hundreds and even thousands of dollars to become members of a "private" club and then spend even more on equipment. In my line of work, money doesn't grow on trees. It doesn't grow anywhere.... Plus, it takes lots of practice and skill to learn how to swing properly and all that. Not worth it.
Football, Baseball & Basketball are for people with lots of friends. Lots of athletic friends... Football is way overrated anyway. Plus all these sports as well as golf and tennis require a court, field or a course. Too much contact as well. Not for me...
Running is an individual sport. No teams or opponents needed, although a partner would be nice for long runs. No "joining fees" or green fees. I don't have to have the most expensive golf club. All I need is a comfortable pair of shoes and an open road.
(Did four miles yesterday, but my iPod messed up and didn't save it. So my goal count is off. )