You can't reasonably expect to get an entire case finished and disposed of at an initial consultation, but you may find that you get a good deal fo information there that will help you moving forward.
If you're looking to have a specific legal question answered, a lawyer will often have you give as many facts as you can, asking questions to narrow the issue. The lawyer can then probably give you some sort of answer, which will be based on her knowledge and experience (although probably not authoritative; it's just off the top of her head).
More often, though, you have a problem and you don't know how to formulate it into an exact question. It's more of a situation where you have to ask "How do I get myself out of this situation?" or "How do I protect myself/my family here?" The lawyer knows that additional work will be necessary in this situation because it will involve litigation or additional paperwork, such as trusts or corporate documents. As a result, the lawyer might just use the opportunity to ask you more questions, and reserve most of the detailed legal opinions for another day.