It was considered impolite to call attention to individual differences of those within the community. Sameness was the ideal within the community. Anything else was a negative thing, and it "was considered rude to call attention to things that were unsettling or different about individuals" (The Giver, Chapter 3). To mention differences could "have fallen under that uncomfortable category of 'being different'" (Chapter 5).
For example, Jonas had pale eyes, while almost everyone else in the community had darker eyes. The only others that Jonas knew with pale eyes were a younger girl and baby Gabriel, the newchild. Yet no one mentioned this difference to him, so as not to be rude.
Later, Jonas noticed that Asher took a daily pill. Jonas did not know why his friend took it. He was curious, but he wanted to avoid being rude. His desire to be polite led him to not say anything.
When Jonas became the Receiver of Memories, he became different. His job was different than anyone else in the community. People began distancing themselves from Jonas.