The problem with self-improvement is knowing when to quit.

I work out more during a full four hours of a football game than I ever do in my workouts.

Consider the perverse effect cap and trade has on altruistic actions. Say you decide to buy a small, high-efficiency car. That reduces your emissions, but not your country's. Instead it allows somebody else to buy a bigger S.U.V. - Because the total emissions are set by the cap.