Diminishing marginal returns is a valuable concept, not only in economics, but in many other areas of life: an obvious example (which we saw in Chapter 9, on consumption) was the diminishing pleasure received by eating successive units of the same food. Suggest two other areas in life that exhibit diminishing marginal returns. Can you also think of some examples in your own life where there are constant or increasing returns to scale (i.e., you get the same, or more, psychic or other "returns" from each additional increment of something)?