He will **never** become a customer--ever.I see it as not punishing the snooty customer, but as giving him a chance to re-evaluate his initial behavior.
After the horrific way he was **deliberately** treated?
He will tell everyone he knows, to avoid the horrible, vain and prideful store owner.
A good customer is a treasure, true.
But a bad customer will tell everyone he knows-- and they will tell everyone they know-- and it repeats endlessly.
If the prideful owner had treated the customer with kindness? In spite of his snotty attitude?
He **likely** would have had a sale, and that'd been that-- end of story.
But since the owner let his **pride** get the better of him-- and he **deliberately** treated the never-again-a customer like crap?
He not only lost **that** customer, he will have lost anyone else that former customer speaks to in the future.
Evil **always** begats more evil.