In the society where Jonas lives in The Giver, sameness is considered important. When everyone is the same, the society has more order. Acceptable behaviors are required rather than recommended. Conformity is expected of the citizens.
Differences are not accepted. When children behave in a way that is considered unacceptable, they are corrected by their parents or teachers. We see this when Lily says something unkind. Asher had an especially difficult time when he was young with following the society's rules. He often was the victim of the "discipline wand," which was a switch used for punishment by teachers. This was his consequence for disobeying the rules.
If a person (be they a baby or an adult) has an especially difficult time conforming, they might be released. This happens to some of the new children who cannot sleep through the night.