Remember the four Ps of marketing - product, price, place, and promotion. We can't display passion or promote a product or service for which we know little or nothing about. Their goals aren't always obvious. Very often a client hasn't got the first clue about what a website is capable of accomplishing for them. Because the client's goals aren't always clear, nailing them down is an important step for both of you.
Clients rightly see their sites as a business tool.
After having gone through their own problem-solving process, the client very often comes to you with a preconceived notion of how their problem should be solved. It is, after all, why you're having your conversation with them in the first place. Ask them point blank what their expectations are. Listen, analyze, listen, analyze. We often make the mistake of putting too much or too little stock in what the client says.