To get everything you want is not a good thing. Disease makes health seem sweet. Hunger leads to the appreciation of being full-fed. Tiredness creates the enjoyment of resting
HeraclitusAll things are in flux; the flux is subject to a unifying measure or rational principle. This principle (logos, the hidden harmony behind all change) bound opposites together in a unified tension, which is like that of a lyre, where a stable harmonious sound emerges from the tension of the opposing forces that arise from the bow bound together by the string.
Heraclitus