No one's mentioned. Keys also serve as a shock absorber. I speculate that years of tapping/rapping/pounding on a glass or hard plastic surface might produce s

No one's mentioned. Keys also serve as a shock absorber. I speculate that years of tapping/rapping/pounding on a glass or hard plastic surface might produce significant joint problems. P.S. I'm referring not just, or primarily, to the force applied, but the the suddenness of the transition to full pressure (cushioned only by one's soft tissue).