Lewis Thomas said this quote

“ Working on a typewriter by touch, like riding a bicycle or strolling on a path, is best done by not giving it a glancing thought. Once you do, your fingers fumble and hit the wrong keys. To do things involving practiced skills, you need to turn loose the systems of muscles and nerves responsible for each maneuver, place them on their own, and stay out of it. There is no real loss of authority in this, since you get to decide whether to do the thing or not, and you can intervene and embellish the technique any time you like; if you want to ride a bicycle backward, or walk with an eccentric loping gait giving a little skip every fourth step, whistling at the same time, you can do that. But if you concentrate your attention on the details, keeping in touch with each muscle, thrusting yourself into a free fall with each step and catching yourself at the last moment by sticking out the other foot in time to break the fall, you will end up immobilized, vibrating with fatigue. It is a blessing to have options for choice and change in the learning of such unconsciously coordinated acts. If we were born with all these knacks inbuilt, automated like ants, we would surely miss the variety. It would be a less interesting world if we all walked and skipped alike, and never fell from bicycles. If we were all genetically programmed to play the piano deftly from birth, we might never learn to understand music. ”