First X said something. Y gave a quick response. X responded to what Y said. Y made an association that turned the conversation in a new direction. X felt misunderstood and raised his voice. Y accused him of being defensive. X hotly denied that. The argument grew voluble. Each became uncompromising. Each was louder and more pointed in an attempt to outdo the other.
Then suddenly he said to himself, Glad that’s sorted out. And he went to bed.