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Just as there are laws of Conservation of Matter and Energy, so there are in fact Laws of Conservation of Pain and Joy. Neither can ever be created or destroyed. But one can be converted into the other.

"Callahan's Crosstime Saloon". Book by Spider Robinson, 1977.
Just as there are laws of Conservation of Matter and Energy, so there are in fact Laws of Conservation of Pain and Joy. Neither can ever be created or destroyed. But one can be converted into the other.