You know what really ticks me off?
When you call customer service for something, because you just have one simple tiny question, and they make it some huge hassle. Like, they need your name and information just to tell you how much something costs.
Sorry, but if you want my all my info (probably so you can then pester me with phone, mail or e-mail solicitations, or sell my info to somebody else who will do the same), you are probably not going to get my business.
If I call a business I already have an account with - my cell phone provider, for example, or my internet company - to see about a rate change, okay, fine, I see where it might be helpful to be able to look up my account information.
But if I'm calling a gym to find out what the monthly membership fee is, you don't need my name, address, and phone number, and if you ask for it, and make one very simple question and answer exchange (Me: "What's your monthly fee?" Them: "It's __ dollars, plus a __ dollar enrollment fee." What did that take? 20 seconds?), take longer than necessary, use up my cell phone minutes (no home phone, why spend the extra money), and generally make it into more hassle than it's worth, you are NOT going to get my business. Because if it's that difficult to find out the answer to one little quick question, what would it be like to do regular business with you?