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 one day—then take a mouthful of cold water, and spit it out again, and tell no man!"
Golden Sayings of Epictetus