Here's an example of what happens when the client's only experience in publication design is the porn magazines in the truck yard's office (at least, I sincerely hope it's the client's limitation, and not the designer's!!)
Trust your experience in design; lead the client when the client needs leading. If you are uncomfortable in the role of educator/consultant/taste arbiter, then take a class in public speaking, or even in sales. It will help your confidence level.
Remember, though the saying is that the client is always right-- they're most right when they knew enough to hire YOU to do this job!
