Free will
Free Will enables the Sims to move without your direction. They can move and do certain actions without you telling them to, if you turn it on in the menu. Most of these actions are in connection with their needs, they do others just for fun.
Free Will is based on a lot: for example, the Beaker's might have it turned on but the Singles's can have it off. When a family moves into a new lot, they will have Free Will on.
Certain things like WooHoo will not be done by Sims with this turned on. You will need to direct them.