When we don't take responsibility, we actively choose not to take care of each other. Instead, we perpetuate mutually destructive relationship patterns. Read more about defensiveness today on The Gottman Relationship Blog.
I think I'd alter this just a bit to say 'If you speak too quickly' when angry... Sometimes conversations have to happen when we're still angry. And extra care has to be taken to stick to the real topic instead of the emotions our reactions invoke. ~RF