It's worse to have lingering conflict for months, years, decades than the pain of direct conflict that can hopefully resolve and move on. If you're angry with people who are close to you, if you're resentful, you're either being oppressed and not standing up for yourself,. Or you're whiny and should grow up. And both of those things are really useful to realize. It's a gateway to improvement, resentment, or you can let it foster it and take you places that no one with a clear mind would ever want to go hell.