It is learning how to argue, and argue well, listening authentically and then not resorting to personal attacks. Civility also does not mean that we must like everyone. In fact, a true measure of one's civility is how we treat people that we really do not like or even respect. We should not teach children to pretend that they like everyone in order for them to be civil toward others. Children learn values such as civility by watching what their parents, teachers and mentors do.
Educators call lessons that children absorb from the behavior of significant adults meta-messages.
Meta-messages are the foundation of behavior, the unquestioned way in which we expect our children to behave. If we wish our children to be more civil, we must model that civility in our actions rather than merely talk about it. Watch our rhetoric. Too often this characterization is earned by Christians who are strident in both their public and private talk. We would do well to talk and listen to all people respectfully, as though God is listening, because, of course, God is.