Don't worry, soon you'll know which bus crash book they want, and you could have found that Shakespeare book - there were only eight options! Just bring the customers to the section and point out the sixty-dollar books on Shakespeare (or the "blue" book on the Kennedy family, or "that" book by C.S. Lewis) and let 'em loose; they will usually find what they wanted, but then buy a different (less expensive) book, anyway. Besides, I'm sure you're doing great.

I'm still baffled that they would train you for customer service first, rather than register. I'd love to know the reasoning behind that, because doing sales and returns is usually much easier than divining what a customer wants.

As for the first guy, at least he was polite. : /