In general, any methods of discipline applied to the body which tend to modify its desires or repulsions, are good—for ascetic ends. But if done for display, they betray at once a man who keeps an eye on outward show; who has an ulterior purpose, and is looking for spectators to shout, ‘Oh what a great man!’ This is why Apollonius so well said: ‘If you are bent upon a little private discipline, wait till you are choking with heat some day—then take a mouthful of water, and spit it out again, and tell no man!’

—Epictetus (Public Domain)