Yeah, customers can be real PIA. About 5 years ago I did all the pricing among other duties for my division. We had one major retailer that was just the biggest bag of (phallic symbol)heads. They would literally spend $100 to fight you over $.23. Ultimately, they pissed me off. Unfortunately for them, I knew how the contract was written and how the system worked.
Needless to say I probably took them for an extra between $250,000 and $500,000 per year, all legit per the contract.
It's one thing to be a phallic symbol if the contractor is screwing up, but it's another when there is no reason for it.