The paying customer is rarely right - it's just a dictum based on the free market philosophy that any sale is better than no sale and in no way entertains the concept of returning custom preferring the quick buck & customer beware basis that big companies can afford but small business must eschew in favour of doing "the right thing". We have professionals & 2nd opinions - IF customers don't like it they go somewhere else - that's the other free market hyperbolic twaddle about choice.
Paying Customer "Dr, Dr, My big toe hurts. Please remove it & stitch it to the back of my head in case I get a head ache & you can remove it from there too"
Dr "I would suggest I look at your toe 1st and see what the problem might be. Oh & how about we remove your penis & put it where your head is since you're such a dick head?"
Paying Customer "but I'm paying you!!"
Dr "that's right & your time is up, goodbye!"
Notwithstanding a modicum of compassion, interpersonal communication skill and a good reason - the message, if you hold your professional or even amateur reputation as valuable, is simple.
Now, if the customer in question would like to pay me by the 1/2 hour for an intership/mentoring program I'd feel compelled to entertain his/her vague inanities.