" What Stoics discover, though, is that willpower is like muscle power: The more they exercise their muscles, the stronger they get, and the more they exercise their will, the stronger it gets. Indeed, by practicing Stoic self-denial techniques over a long period, Stoics can transform themselves into individuals remarkable for their courage and self-control. "

― William B. Irvine , A Guide to the Good Life: The Ancient Art of Stoic Joy