The Brahma Vahara: The Heart Practices

The Buddha said one expression of anger could annihilate a thousand years of kindness. The near enemy of loving-kindness is sentimentality, which is what you're talking about. With compassion, of course, you're opening to the suffering experience of other people and not repelling it through an expression of cruelty. One couple's relationship could be salvaged in therapy based on expressions of contempt.