I wonder if this is a verse about attitude or motive. The action is praiseworthy. We are to bless people, even our enemies.
(Romans 12:14 KJV) Bless them which persecute you: bless, and curse not.This is what turning the other cheek and going the extra mile involves. The problem inferred here is that we can cancel any good we do if our motive is not right. A loud voice early in the morning says you are either trying to irritate or trying to impress.
What does this say about other things we do in life? I think the same principle applies.
So? It is good to do the right things. It is vital to have the right motivation. Other people may not know but you do and so does God.