Life isn’t fair. This is a rule that it is best to learn early and to learn often. You can’t always expect to get the same thing as everyone else. You learn this extra early if you have siblings. You might see that your parents were probably stricter with the first child than they are with the second. You might notice that your sibling is taller or more attractive than you, or has more friends. Maybe you’re smarter than your sibling and get better grades. Even though you technically have the same genes and the same upbringing. Nothing is totally even in life. If you split a cookie down the middle, odds are one side has more chocolate chips. 

This is important to learn so you can develop self-esteem. Even though not everything is fair, everyone should be equal. If you learn the difference, it’s easier to understand. This is the job of parents to do.