A bitter-tongued parent cannot teach respect for facts. Truth for its own sake can be a deadly weapon in family relations. Truth without compassion can destroy love. Some parents try too hard to prove exactly how, where and why they have been right. This approach will bring bitterness and disappointment. When attitudes are hostile, facts are unconvincing.

Haim Ginott (1922-1973) Israeli-American school teacher, child psychologist, psychotherapist [b. Haim Ginzburg]

Between Parent and Teenager, ch. 2 “Rebellion and Response” (1969)
    (Source)

Sometimes mis-cited to the earlier Between Parent and Child (1965).