I appreciate that John explained to me the process of the catalytic converter and oxygen sensors with repair options. At two other repair shops, they treated me like a dumb twit. Although they treated me (at first) with knowledgeable explanations (saying all the time), that they wanted my repeat business.
It is very rude to give bland explanations to customers, without finding out what the customer knowledge base is.
As in my case, every penny counts. (And every teaching opportunity for car care.)