How often has your peaceful shower been interrupted by a gush of totally freezing or steaming hot water? Someone may have started the washer or dishwasher. Perhaps someone flushed the toilet in another bathroom? The water temperature and pressure usually simultaneously change.
Installing a pressure balance device on the faucet that feeds the shower is an easy way to eliminate this problem. You may also consider replacing the faucet you currently have with a pressure balance faucet.
