I am not sure how thrilled I am to be basing this post on an insight I got from Sam Harris, but it is one of the best analogies for free will I have seen. This is based on a recent post on his blog, although taken in a different direction (as I am sure you knew I would). When we watch movies, we have the illusion that the image on the screen is continuous. Deep down, most of us know that it is really 60 static frames per second. But concentrating on that would ruin the movie. Putting the knowledge aside to improve life experience is OK.
We can think of free will the same way. Perhaps neuroscience can demonstrate that every decision we make is a combination of past experience hard coded into our neurons, culture that is hard coded the same way, and genetics that started out hard coded - with just a bit of stochastic randomness thrown in. But behavioral science demonstrates that concentrating on this leads us to less ethical and less dedicated behavior. So human experience is improved by putting the knowledge about free will aside and acting as if we had the full control of our will that our perceptual experience tells us.
And that’s OK.