The citizens of the community have every aspect of their lives controlled by Sameness.
In Jonas’s community, the world is very predictable. Everyone in the community has to follow strict rules and there are no second chances. Any citizen who breaks the rules, or makes a mistake, is released.
For a contributing citizen to be released from the community was a final decision, a terrible punishment, an overwhelming statement of failure. (Ch. 1)
Release is just one of the community’s ways of controlling its citizens. There are also rules for everything, and rituals to control emotions. Everyone participates in rituals designed to control either behavior or feelings. Examples are, the evening telling of feelings and the morning telling of dreams. These, as well as obligatory apologies for minor infractions and taking pills for “Stirrings” (sexual feelings), keep the community members in line.
The community also carefully creates family units. Family units are created by taking two adults and pairing them, and then assigning them two children. They are assigned one boy and one girl, at different times. The adults feel no love or affection for one another. They are just assigned to raise the children.
Each of the babies are genetically engineered and come from birthmothers. Somehow the scientists who ensure Sameness make sure that everyone in the community looks alike. We know this because Jonas is one of very few people with light colored eyes, and Fiona is the only one with red hair. The Giver explains:
"We've never completely mastered Sameness. I suppose the genetic scientists are still hard at work trying to work the kinks out. Hair like Fiona's must drive them crazy." (Ch. 12)
One other aspect of the community is that they have no sense of history. This is part of Sameness. All of the community’s memories are stored in The Receiver, who keeps them safely locked away. This prevents anyone in the community from needing to feel the pain associated with those memories.
Of course, there are some good things in those memories too, such as love, but it is safely stored away as well. Anything that would cause anyone to feel emotions is locked away. This protects the people from feeling any extreme emotions either way. They have chosen to eliminate the good with the bad.