" He said there were two kinds of bitterness: one that takes away the appetite and one that stimulates it. Pepper, he said, was of the first kind - it burns the tongue and nothing more. But horse-radish, though bitter, sharpens the hunger and makes a man impatient for the good things of the meal. So, he said, if a man becomes only bitter and downcast he goes no further. But a little bitterness, a little horse-radish, may give one an appetite for perfection.
"How quaint," said Ogle, "how undeniably folksy. "

― Guy Vanderhaeghe , Man Descending: Selected Stories