Some train or teach to show off. These people usually like to explain things to everyone who will listen. Some of these people have nothing worth listening to. Not to say that everyone who displays ability or explains how they perceive Karate is bad. But if this appears to be the reason that one goes to the dojo, there may be a problem.
Some instructors teach to make money.
Although I have no problem with charging for classes and even living off this money, many instructors who have money-making as the main goal of their teaching lose their love of the art and stop trying to learn more themselves. Making money through teaching Karate is fine. But that should not be the all-encompassing reason for teaching. Somehow, he passed. Don't worry if you don't have the perfect answer when people ask you why you do Karate.