For lunch, I have the choice between rice and pasta. I enjoy both equally.

I had rice yesterday, so for sake of variety, I am leaning towards pasta.  The sauce and noodles are already made and will be ready to eat right now.  Rice sounds really good though.  Never mind that I will have to prepare it and wait for around and hour for it to be ready to eat, I really want some rice today.

Now, this might not truly be a free choice.  Any number of external factors or chemical reactions in my brain could be guiding me to take the "harder" path.  The number of factors can be considered infinite for the sake of my very finite brain.  I cannot even begin to comprehend the vastness of the factors influencing my every decision.

So does free will exist?  Maybe not, but for all practical purposes, I can live my life believing it does.  My choices will be the same, and I will live with the consequences either way.

Perhaps the very belief that free exists can itself add another variable to the deterministic equation.