"Whether you are a parent, a minister, a healer, or a CEO, your communicant's capacity to hear you depends primarily on the emotional variables of direction, distance, and anxiety. Others can only hear you when they are moving toward you, no matter how eloquently you phrase the message. In other words, as long as you are in the pursuing, rescuing, or coercive position, your message, no matter how eloquently broadcast, will never catch up." - Friedman, A Failure of Nerve, p128.
Anxiety, in particular, he mentions, works like static in the conversation, making it impossible to hear the other. Turn up the volume on the message and the static only goes up as well because anxiety increases.