"If you don't have anything nice to say, don't say anything at all" is probably something we can all carry with us. Remembering that the person we're addressing is a creation made in God's image is certainly a good reminder when we're thinking of how we want to approach someone else. Of course, this becomes difficult when we try to put it into practice. People cause us pain and wrong us. Difficult though it is, this is certainly the way Jesus was treated as well, and he is the one we claim to follow.