If any man can convince me and bring home to me that I do not think or act aright, gladly will I change; for I search after truth, by which man never yet was harmed. But he is harmed who abideth on still in his deception and ignorance. — Meditations, Book VI

My Take – When you hold to your idea of what is and what is not, even when shown incontrovertible proof to the contrary, you move from the realm of knowledge into the world of belief.  Now, there’s nothing wrong with beliefs.  We all have them, but they’re not facts.  Every time someone, with respect and consideration, shows you a new way or tells you a new fact, you should evaluate its truthfulness, and if it passes the sniff test, incorporate it into what you know and what you do.  “We’ve always done it this way” or “That’s not what I was taught” are excuses to not learn, and once you stop learning, you start to stop living.  Old dogs learn new tricks all the time, they just have to remember that the old ways aren’t the only ways.