This section is from the book "Elementary Economics", by Charles Manfred Thompson. Also available from Amazon: Elementary Economics.
The most obvious illustrations of the law of diminishing utility are found in the consumption of food. A healthy boy with a plate of apples before him will eat the first one eagerly. The second he will consume with relish. Likewise, the third, the fourth, the fifth, and perhaps the sixth yield satisfaction. Finally, no matter how great his appetite may be, the point will be reached when he cannot eat another one. This point of satiety could be pushed ahead somewhat by substituting other kinds of fruit and especially such foods as meat, potatoes, and bread, thus offering a variety. Even then the law holds true, though its operation is not so easily seen as it was in the case where apples alone were considered. As it is with food so it is with all other consumable goods. One suit of clothing is a necessity. A second suit for Sundays and holidays is desirable. A third suit perhaps would serve a good purpose. Each yields less satisfaction than the preceding one, until finally the most fastidious dandy in the world would not care to have another. Obviously, as in the case of food, the satisfaction derived from each additional suit will diminish more rapidly if all the suits are exactly alike; yet no matter how great the variety in color, texture, weave, or style, the law of diminishing utility holds true. Occasionally there are outstanding exceptions to the law, which, however, do not invalidate it. The first mouthful of some foods often gives less satisfaction than the second or third. Because of this fact many persons are compelled "to learn" to eat, for example, oysters or olives. Similarly, some habitual drinkers find that they like the second or third glass of liquor better than the first.
 
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