'..."good disagreement" must allow for situations where "agreeing to disagree" cannot be justified. Broadly speaking, most Christians accept that there are issues of doctrine (e.g. the uniqueness of Christ and redemption only through him ) and ethics (e.g. the rejection of injustice and sexual immorality) which are more important than issues of ecclesiastical order (e.g. ordination and infant baptism) because they reach to the heart of the good news about salvation. Applying the language of "good disagreement" in an identical way to all disputed questions, as if they are equivalent, leads to confusion and fails to distinguish their relative importance. On some issues, it may require discipline, differentiation, or even some form of separation among professing Christians - in which case its "goodness" will be evident by the continuing witness to God's grace and truth in how we walk apart: in humility and sorrow, with blessing not cursing, with gentleness not venom.'
Andrew Atherstone & Andrew Goddard, Good Disagreement? p.18.