The downside is the arguing and hurt feelings, the tears and the jealousy. They learn other children also want the biggest piece and the first turn. They learn other children feel bad when they have to wait or when someone pinches them. Children who only play with adults or older children never have the chance to work out their friendships as equals. Children who are rejected by their peers or have no friends are at risk for later emotional and mental health problems, dropping out of school, delinquency, lower grades, a harder time adjusting to school and a negative outlook about school.
Friends are important to a growing child.
Parents provide nutritious foods, plenty of rest and exercise to help their children develop physically. Practice at being a friend is just as important to social and emotional growth. Some don't share until much later if they haven't had practice at it. Parents can expect some arguments, perhaps threats, bribes and other unpleasant ways of dealing with people. Try not to get involved unless you are asked to or if someone is going to get hurt.