Illustrate the "Law of Diminishing Marginal Utility" in tourism consumption with an example.

The law of diminishing marginal utility (the law of diminishing returns) is one of the basic laws of microeconomics. It refers to the law that when a certain input is continuously increased while other inputs are fixed, the newly added output will eventually decrease. Another equivalent way of saying this law is: after exceeding a certain level, the marginal product of marginal input decreases. You open a small workshop and can produce 5 items per day, so the efficiency is 5 items/day. Your business is getting bigger and bigger, and you need help, so now you have two employees. When there are more people, chatting at work misses work, and two people rely on each other, hoping to be lazy and save effort, so the efficiency becomes 4.5 pieces/day. When the salary and other incentive systems remain unchanged, the output efficiency will be higher. Come smaller and smaller. Eat ice cream. If a certain girl can eat ice cream, but 2 are just right, I think she must be very delicious when she eats the first one. The second one is okay, and the third one will probably start to hate it. She will probably hate it after the fourth one. I guess she will when she hates the fifth one quite a lot. . . . .

ZZZZZZZI think the utility function of her happiness and anger can be y=y(x). Among them, the number of ice creams x is obvious, and the utility is decreasing.