The community in the book has chosen Sameness because they do not ever want anyone to be uncomfortable. Everyone follows the rules, and everyone does the same things. People don’t have individual identities, but they don’t have social problems either. People who commit three infractions are killed. There is no overpopulation, because no one has their own children. There is no emotion, no love, and no memory. There are no good emotions, but there are also no bad emotions.
Although there are few differences, they keep enough individuality amongst the people to avoid confusion. Consider Jonas’s explanation of why there can’t be identical twins in the community.
"Well, they can't have two identical people around! Think how confusing it would be!" Jonas chuckled. (ch 19, p. 146)
Sameness also means no love. When Jonas asks his parents if they love him, they scold him for not using precise language.
There was an awkward silence for a moment. Then Father gave a little chuckle. "Jonas. You, of all people. Precision of language, please!" (ch 16, p. 127)
Amusement is the last reaction Jonas expected when he asked that question, but he realized at this point that his parents have no concept of love. A society without love is dehumanized. Jonas cannot stand it, so he leaves—hoping to return the memories to the people and bring about change.
Lowry, Lois (1993-04-26). The Giver (Newbery Medal Book) (p. 146). Houghton Mifflin Harcourt. Kindle Edition.