Deteriorating Communication:
Personal Attack
This occurs when the disagreement intensifies, and the other person's behavior, character, personality, family, background, etc. is attacked.
Statements like 'I'm sick of your laziness', or 'You are stupid and dumb' may seem like the issue, but cannot resolve the disagreeement, because it is a personal criticism.
The result is that the other person will almost always defend themselves by a counter-attack on your personal character.
Stay with the Issue.