Courtesy begins at home

I think that courtesy begins at home, as that is where children learn from their parents to be a courteous person. At home, a child's parents correct his/her mistakes and teaches her the correct morals and how to be polite. A parent also teaches his/her child table manners and how to behave in the public.
However, children can also learn to be courteous in school where they have more exposure to other students. They learn how to treat their classmates courteously, as well as learn how to be considerate from their teachers.
Thus, I think that courtesy begins at home, where the child learns from his/her parents, but can be enforced in school or in the public where the child receives much more exposure and the experience of dealing with others.