Reputation

This is a feature that was added in the Apartment Life expansion pack. If you done enough friendly interactions with a townie, they would mention "You are simply the coolest person I've ever met! Keep it up, and your reputation is going up! I'm telling all my friends about you!". After you gain enough reputation, it's easier to make friends. If you get a Romance or Popularity Sim to earn enough reputation, you can get a really sucsessful sim.