What phenomena in life can be explained by economic principles?

In life, many phenomena can be explained by economic principles. Take the ten principles of economics as an example:

The first principle is that people face the problem of trade-offs. For example, when buying fruits, we can choose from three kinds of fruits, one is apples, the other is watermelons and the other is bananas. We can only buy one kind of fruit at a time. So if I buy apples, that means I will give up the chance to buy watermelons and bananas. Similarly, if I choose to buy watermelon, I give up the opportunity to buy apples and bananas. If I buy bananas, I give up the opportunity to buy watermelons and apples. Tian Ji horse racing is also a well-known routine to weigh the maximum benefits.

Principle two, measure the opportunity cost by the value of what you give up. Just like the choice of going to college involves a great opportunity cost. If we don't go to college, the salary we get is twelve times three, which is one of the opportunity costs we give up in three years. In addition, we have to pay a certain tuition fee to go to college, and this tuition fee multiplied by three is the real cost we pay.

Principle 3: Use the comparison of marginal cost and marginal income to make a choice. Many decisions in life involve small incremental adjustments to existing action plans. Economists call these adjustments marginal changes. In many cases, people can make the optimal decision by considering the marginal quantity. For example, the ticket price was originally within 200 yuan, but due to various factors, all the tickets for this flight were not sold out. Now the captain offered to sell the tickets at the price of 100 yuan. Is this feasible? The answer is, of course, yes. If the ticket is sold at the price of 100 yuan, its marginal cost may be the drinks or meals that passengers drink on the plane, which is definitely less than 100 yuan. But if you don't sell the tickets, you will lose the price of many tickets for nothing. Therefore, it is concluded that the marginal revenue is greater than the marginal cost, and rational salespeople will dispose of tickets at a low price instead of losing their value in vain.

Principle 4: Consumers' preferences and expectations for the future affect their consumption choices. Because people make decisions by comparing costs and benefits, when costs or benefits change, people's behavior will also change. In other words, people will respond to incentives. For example, if the price of apples increases, consumers will eat more pears and less apples, because the cost of eating apples is high. Orchard owners will increase planting and harvesting personnel to increase production, because the price increase of apples can increase income. In addition, when the taxi price is low, people may choose to take a taxi, but after the price rises, people will choose the bus with lower price.

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