What Sim character trait is most important to you, and why?

For me, the most important traits are the ones earned through parenthood. I know they can't be directly assigned, but for me they have the most impact on game play. Having sims earn the well-mannered trait is a blessing, as being able to use the polite introduction almost instantly allows you to befriend other sims! And the responsible trait is so important because it makes the daily career task always complete. To me, those two traits have more of an impact on gameplay than any other trait you can assign your sims.