You use only 10 percent of your brain. Have you ever heard that? It’s nonsense. You and I use our whole brains. Ask any neurologist. There are no idle parts of the brain, no brain cells sitting around unused. For example, there are neurons in your brain stem whose job is to immobilize your body while you’re dreaming so you don’t physically act out your dreams and get up and run into a wall. Every part has its function.
Idiot-savants can be a genius at one thing, like mathematical calculations or music, but they pay for it with a corresponding deficit in other useful attributes, like getting along with others. What happens is that one function, like mathematical ability, takes over a larger percentage of brain tissue — commandeers it, so to speak, usually as a result of a brain injury at birth — but whatever other ability that part of the brain is normally used for goes wanting. What you often get are geniuses that can’t have a decent relationship or tie their shoes or control their emotions.
All those abilities require brain space, and there’s just barely enough with none to spare. Nature did not equip us with a bunch of extra brain cells. As it is, the brain is as big as it can get and still (barely) make it through the birth canal. If it were any bigger, normal births would be impossible.
You could learn more, do more, be more, for sure. But there is always a trade-off. You could use every spare moment, for example, listening to language tapes, and thereby learn ten more languages in your lifetime. But it would have consequences. You’d have less time to socialize, for one. And that would have other, possibly negative, consequences.
You could work all the time, always improving yourself at every moment of the day, but no play makes Johnny a dull boy. It’s a trade-off. Balance is the key.
So don’t feel bad that you’re not “maximizing your full potential.” Devote some time to your betterment, but also relax and enjoy the ride. You’re alive on the planet, breathing air and capable of communicating with other fellow travelers. Enjoy it.