Give said sim a bad habit: anything from constantly drinking to playing video games to burning/eating herbs to the bubble hookah to seeking Woo Hoo with everyone in sight. Childish and Dramatic can add flavor and more possibilities.
In contrast to The Sims and The Sims 2, the game placed more emphasis on the neighborhood by making it all accessible in real time and making all families age and evolve along with yours, but this could be turned off. The Sims 3 is the third standalone game in the The Sims series, released in 2009.