A student told me that his father had a habit that used to annoy him. It was a minor habit, but he found it irritating. His father would frequently say, "You know" when he spoke. As politely and respectfully as he could, he had pointed this out to his father. His father told him that he wasn't aware of this, and he would try to avoid it. But this habit was so entrenched that it wasn't so easy to just stop saying, "You know." As his father would say, "You know, everyone has such habits."
I suggested to the son that when his father said, "You know," he should think to himself, "What am I grateful for right now?" Let the habit of his father create the habit in his own mind of asking this gratitude enhancing question.
The son reported to me, "First of all, I have a tremendous amount of things to be grateful for about my father. In a short time, my mind would think of, ‘What are you grateful for right now?' whenever I heard anyone say, ‘You know.' Now I am even grateful that my father says, ‘You know,' since it has made me a much more grateful person."
(From Rabbi Zelig Pliskin's book: THANK YOU! Gratitude: Formulas, Stories, and Insights: Artscroll Publishers)