Cal Evans has posted his third tip for clients wanting to have a better relationship with the developers on their project. This new tip talks about the balance between suggestions and "being sold" on technologies.
To balance Point 2, make sure your developer fully understands the problem and has put thought into it before actually proposing a solution. If, in the first meeting they propose a solution, especially a pre-packaged solution like WordPress, Joomla or Drupal, exit the building in a calm and orderly manner. In these cases they are selling you the solution they know, not the solution you need.
He suggests that you tread carefully when it comes to software choices and don't blindly follow the suggestions handed to you. A little research is all it takes to see if their proposal is actually a good fit. Ask a lot of questions and really think about the answers before moving on.