The last time I was in Circuit City I knew exactly what I wanted, found it, and only needed a "sales associate" to order it up to be at the checkout area for me to pay for and take home. (For those unfamiliar with that store, all fairly large or expensive items only have one actually in the customer area, and a sales person has somebody physically deliver a boxed item to the checkout area. Thus, you can't avoid needing sales staff for anything but small stuff.) I asked THREE times and was blown off, while the guys were playing video games and cat-calling back and forth and not busy helping anybody. Finally, I went to the checkout area, asked to speak to the manager, and told him that I came into that store to purchase a rather expensive item but was repeatedly unable to get assistance to get the article in hand and pay for it, but the sales staff was apparently too busy polishing their video game skills. The manager said he'd get the item immediately, and I told him I had already decided to purchase it at the competitor down the street, but merely wanted him to know that the store had lost a fairly large sale. And I left.
When I was leaving the local airport parking lot a few years back the guy in the booth tried to charge me exactly double what the lit sign said after it totalled up the time the car was in the lot. I told him the sign said $10, so what did he mean asking me for $20, and he said it was a long story and just to pay it. I said I could wait for his explanation, put the car in "park", and smiled at him expectantly. Suddenly the charge was $10, which I paid and left. However, within minutes I was on the phone to the airport manager, and when the manager tried to justify the employee I said my next call would be to the chairman of the airport authority, and possibly followed by the local newspaper. I did call the chairman of the airport authority in his office the following morning, and a few days later when I was back at the airport I noticed someone different in the booth.
When I had a small deposit box and savings account at a bank near my office, I went to the bank over lunch hour to pay the annual rental, and since I paid with cash I asked for a receipt. Fortunately I saved the receipt, because the next month I got another bill for the same thing! I made a photocopy of the receipt, took the original and the copy to the bank at lunch hour, showed them the original, gave them the copy, and asked them to correct the records. Next month, same thing, with the addition of a rather terse letter about late payments! However, when I went to the bank that time, again with the original receipt and another photocopy, I asked to speak to the manager. I was told there was no manager on duty, which I reminded them is violation of federal banking law -- whenever a bank is open, a manager is required to be physically present and on duty. Amazingly, a manager appeared. I told him I had paid, showed him the original receipt, gave him the photocopy, and told him they needed to correct their records immediately, because if they drilled the box and sold the contents for non-payment we would be in court and that I would be certain to subpoena federal banking regulatory officials to explain the banking laws to the court as well as the state Attorney General concerning the consumer fraud laws. He almost tripped over his tongue! Later that day I secured a deposit box at another bank, and the following day went to the bank, removed the contents of the deposit box, returned the keys, asked for pro-rated return of the rent I had paid in advance, and closed the savings account. Again, the manager appeared, but without my asking for him, and asked me why I was leaving the bank! Sheesh! And they expected to continue to handle my money, too . . .
I try to be polite to everyone, and avoid raising hell with clerks and other employees, but never hesitate to speak to management. Fortunately, the vast majority of stores, banks, service stations, etc., are very good to deal with.