It isn't necessarily what I say, it is how and when I say it. I can say "you did this" or "you didn't do this" and it invokes a negative reaction. It breeds defensiveness. When I use the same subject and phrase it differently. "next time can we do this" or "I need you to do this" it draws the opposite reaction. No defensiveness, just calm and understanding. Willingness to change and make the situation better for me, because in every case I am the only one who sees flaws in what has happened. I'm the only one who knows, so naturally I am the only one responsible for making things come out differently in the future.