The Federal Civil Rights Act ensures citizens they cannot be refused service in a public place or by a business because of race, gender, sexual orientation, etc. However, court cases support the idea that businesses (therefore mechanics, salesmen and parts people) have the right to refuse service, as long as it's not because of race, gender, sexual orientation, etc.
So at what point is an employee of a business justified in looking a patron in the eye and saying, "I'm not going to work for you," or "Please leave, I will not serve or wait on you"? How much rudeness, profanity or verbal abuse is justification for denying a patron service?
Years ago a farmer friend made repeated trips to a farm supply company to get parts for a sprayer. This friend is admittedly profane, excitable, extremely vocal and easily frustrated. After the third or fourth trip my friend lost his cool, cussing, swearing and raising a ruckus at the business's service counter. The business owner told my excitable friend, "I've tried to help you, but this isn't working out. Please leave. We will no longer do business with you."
My friend was outraged.The local coffee shops percolated for weeks whether the business or my friend was "in the right." At the time I thought it was wrong for the businessman to turn down potential income simply because he didn't want to deal with an excitable, irascible customer.
Now that I've spent nearly two decades working in the service sector, there are times when I'm sympathetic to that businessman's decision.