I really loved this analogy, it is very pertinent to us here because we are currently working with about half a dozen auto recyclers, upgrading their websites.
A user won’t wrestle with your site. Web design, particularly navigation, is not the place to get clever. Web design should be no more complicated than book design. You might notice every book shares the exact same user interface. As do cars. As do bicycles. I have no idea how my car works. People have explained the workings of the internal combustion engine to me, and I nod sagely, but really, I don’t have a clue. Nor do I need to know. I just turn the key and hit the pedal. Your website design should ask nothing more of the user than a car does. Assume nothing, other than the user will point and click something obvious.