If ones bowels move, one is happy; and if they don't move, one is unhappy. That is all there is to it.

In characteristically earthy, humorous fashion, Lin Yutang reduces “happiness” to a blunt physiological baseline: comfort in the body. The line satirizes lofty, over-intellectualized theories of well-being by insisting that much of what people call happiness depends on ordinary bodily functioning—health, ease, and the absence of discomfort. It also echoes a traditional, practical strain in Chinese thought that values harmony of body and daily life over abstract ideals. The provocation is not merely scatological; it is a reminder that grand philosophies can ignore the simplest determinants of mood and contentment.