For example, if you're a runner like me, you can't just run all the time and not expect something to go wrong, be it an injury or just plain boredom. The healthy runner mixes in a variety of other activities - including rest - to balance out his or her life. Taking the time to warm up before and cool down after are extremely crucial to maintain health. Simply running doesn't make you a stronger or healthier person. A healthy runner also will engage in other forms of exercise like biking, hiking, swimming...even dancing.
This balance is absolutely vital because too much of a good thing does exist. Fruit is good for you, but if all you eat is fruit, you won't get the carbohydrates your body needs from grains or the vitamins in veggies that fruit lacks!
The above examples seem obvious. That's because they are. Where things get fuzzy is being able to see how these "laws" of physical experiences translate into metaphysical experiences - the relationships, thoughts, and other parts of out lives we can't taste or touch - yet it is a fundamental ability in self-improvement. In the same way we must balance our food intake, we must balance our social interaction with our solitude; our work with our play; our time spent dreaming about the future with our time spent living in the present. This list goes on because balance truly applies to everything.
I haven't even grazed the surface of the critical role that balance plays in our lives, so I'll be talking about it again soon.
P.S.: Feedback is always appreciated!