Enjoy the ride

Something I'll never understand is why more people don't try commuting or running errands by bike. Millions of people ride bikes for fun and exercise, yet when it comes to getting somewhere they could easily travel to by that same way, they choose a way that costs them money and is generally frustrating. No one likes being part of a traffic jam, yet most of those same millions who ride a bike for fun leave it at home and choose getting stuck in traffic in their cars instead. Yes, there are some circumstances that might "necessitate" driving: working more than 10 miles from your home, grocery shopping for a family of 15, etc. But most trips aren't actually for those purposes and are only a few miles, which is quick and easy to cover on a bike. Why not save the money and ride your bike? Study after study shows bike commuters are among the most satisfied commuters (I'm sure even those that control for our smug-induced happiness). Yet people don't seem to get it or try to make a change. Why?