civility costs nothing
It is easy to be respectful. You don't have to be their best friends, but you could at least say hi to them—civility costs nothing.
Civility costs nothing.
and Courtesy costs nothing.Prov. It never hurts you to be polite. Always greet people politely, no matter what you think of them. Civility costs nothing. Why not write Mildred a thank-you note? Courtesy costs nothing.