Customer refuses to accept quote estimate, complains when developer refuses to haggle and instead rejects their business:'You don't wanna pay the estimate, that's fine ma'am enjoy your day'

"Bend over backward to solve their problem today, and they become your problem permanently."

Earlier in my career, I worked in retail stores with attached workshops that provided maintenance and break-fix work. I received the above sage advice from a wizened and weary mechanic who had been dealing with unruly customers for far too long.

See, there are plenty of people in this world just looking for attention by creating problems for someone else to solve for them. If you make it your duty to help them, they'll identify you as someone with whom they can constantly and incessantly pursue—basically inventing problems for you to solve for them out of habit. Eventually, when you've had enough and attempt to fob off their constant requests, they'll hit the roof and go full nuclear, escalating their "issue" above your head and causing general havoc. 

Deciding not to help these people might fly directly in the face of the usual retail mentality that you should give the customer whatever they want. But by this point, they will have done nothing but waste massive amounts of your time. Do this enough, and you'll quickly have a collection of these returning "customers" who do nothing but waste your time, generally spending very little but demanding lots. With some experience, you can identify these types from miles away.

This is a story of how this software development estimator ran into one of these types, and quickly realized that their organization was better off without their business.