The newest Sims 3 expansion, The Sims 3: Ambitions, isn't going to change your mind about the biggest PC gaming franchise ever. It doesn't radically reinvent the series, but it is much more substantial than I think a lot of people give Sims expansions credit for being. This isn't just a few new outfits or the ability to have a pet (though it does, of course, add new features both major and minor), this expansion radically alters the way characters pursue their careers, making for a more satisfying Sims experience. 

In Sims 3 the main appeal is running and observing the life of your Sims -- little avatars you can give commands to. After creating your Sims -- which is a worthwhile thing in Ambitions, since several new traits and life goals have been added -- you get to jump into a large town and start deciding how you want them to live their lives. Previously you could dictate almost all their actions, with the notable exception being their job. Sure, you could pick their career, and in some cases you could directly control their livelihood if they were making ends meet as an artist or musician, but most jobs boiled down to your Sim disappearing during the day and you collecting a check when they were back. 

Who you gonna call?

Be a hero.