A lot of fun stuff happens when you go out on a bike compared to when you're in a car. You're more in the environment. It's enjoyable. Even when It's raining It's still fun.
Well, you go to Holland and everybody's on a bike - nobody would think to have a car.
I think if you exercise, your state of mind - my state of mind - is usually more at ease, ready for more mental challenges. Once I get the physical stuff out of the way it always seems like I have more calmness and better self-esteem.