To Zdads analogy to buying a car,
What about if you had done all your research and spent hundreds of hours figuring out just what you want in a car and which car and what it should look like and how it should perform and what specifically you need a car for, and then you pick out a car. Then you go to the showroom to look at a car exactly like that. How much time do you then need to close the deal, perhaps a quick test drive to see if it is what you think it is based on your research. The test drive will be much more focused and to the point.
On the other hand, if you do not do the research before and just take cars for a test drive, how do you know you are going to get whats best for you? Or even what you need.