enthusiasm is a mental construct that allows him to focus his mind and body on the goal at hand, even when he doesn't feel like it. In other words, its bethe unsmiling version of will power. If i were interviewing garry, i would ask him to complete the zest scale. That would make so much more sense.
What’s the difference between willpower and eagerness? Is there a lifehack that can make you zestier? And could it help Stephen improve his golf game?