The Customer is not always right

Earlier today, i stepped into madam no time's salon to get my nails polished and i was attended to by a young boy of roughly 13 years. I met him working on someone's nails and I had to wait for my turn, i observed he had a rapport with the lady.
While he was working on my nails i noticed him struggling to start a conversation but i was uninterested until he finally asked "why do people say the customer is always right"?. I looked up at him in astonishment, then he continued," to me o, the customer is not always right ", he was of the opinion that a lot of customers misbehave and hide under the shadow of" THE CUSTOMER IS ALWAYS RIGHT ", he told me stories of how customers denied getting their balance from him after payment, how they took things without paying, how they didn't trust him to do a good job and ended up messing up the whole work with their plenty adjustments and ideas and the blame went back to him.
He was really displeased because no one ever gets to hear his own side of the story.
A lot of entrepreneurs are faced with the challenge of having to deal with difficult customers while trying to grow their business.
As an entrepreneur you should have it in mind that having difficult customers is inevitable but you should know when to cross the line and draw the curtain, you should know which ones is worth the stress and which ones to let go.
Your business needs to succeed so have it in mind that THE CUSTOMER IS ALWAYS RIGHT DOESN'T MAKE THEM THE RIGHT CUSTOMER.
And by the way, the little guy did a great job, i look forward to enjoying his service again