We had a new client come in the other day who asked our fantastic instructor Neil Holland about why we don't do aerobic exercise (and a few other things like stretching) at Serious Strength.
To be clear, he asked Neil the question. Neil did not launch into a sermon on the subject out of nowhere. Like the uber-instructor Neil is, he answered the client as thoroughly and as specifically as he could.
The client, while listening, became pensive. Neil was obviously telling him things that flew in the face of what he already believed to be true about cardiovascular/aerobic training and this put the client, or rather, the client put himself on the defensive.
Neil told him many things that are scientifically true - facts that are inarguable. Yet, the client refused to accept the information in favor of what he already thought was true. This situation, as you might guess, happens from time to time when you educate people that aerobic exercise pales in comparison to resistance training at providing virtually every possible physiological benefit including cardiovascular benefits.
As the client listened and grew ever more discombobulated, he told Neil that he was being "arrogant." But was he? No. Neil wasn't being arrogant, he was being honest and providing the information asked of him with certainty. Certainty isn't arrogance but it can be perceived as such when educating someone who already believes something that is completely incongruous to what you are saying to them.
This is a good lesson for all instructors/personal trainers to learn from. And anyone else for that matter.
Whenever you are in a similar situation, before you launch into the facts, first assess your audience and tailor your talk to them so that they can "hear" you. It won't work very well if you flat out tell a vegan that meat is more nutrient dense than vegetables. They'll just freak.
But if instead you agree with them that vegetables are highly nutritious and berries are the gift of God and then mention that, while killing animals for food certainly can be considered abhorrent, meats and fish do contain all of the vitamins and minerals people need, you at least have a shot of them accepting that fact.
A very good book for helping anyone to communicate better is Crucial Conversations: Tools for Talking When Stakes Are High
After reading this book, you'll be able to sell catnip to a dog - or maybe even meat to a vegan!