People shouldn't take more than they need.
Fernando is a hungry student at school and is in the cafeteria to eat lunch.
Fernando wants to get food.
Fernando gets one plate and returns for seconds according to his hunger level.
Fernando takes an extra plate of food in case he doesn't get enough, then fills up before he can eat it all.
The cafeteria makes good use of its food and doesn't waste much of anything.
The food is thrown out and the cafeteria has to pay extra money for the waste.