The Sims 3 allows you to create your own virtual person and let that Sim lead their own life. When creating a Sim, you have the freedom to give the Sim personality by determining all kinds of behavioral traits.

You will be given the choice to fulfill your Sims desires or not. Through Karma Powers you can directly influence the lives of Sims with strange events. For example, you can influence the karma of Sims by making them extra happy, giving them a nice appearance, or causing bad luck.