Mutual understanding is the key to a successful relationship. If one doesn't understand the needs and wants of a partner at any given time, provided the partner can physically and mentally do it and still decides to not do it. Then that could lead to problems. I think in a relationship, both individuals should respect each other and understand the circumstances before jumping into an argument because that ends up putting a blame on either one of them which could lead to bigger problems down the road. (This is coming from a personal experience)