You're welcome
@racheliz , and welcome to the forum, by the way! You don't need to tag anyone. It's up to you
. However, it is helpful. The evil sim moodlet probably was from speaking with an evil Sim at work.
You can change a Sims' traits by using a cheat.
1. Open the cheat console by typing control, shift, c at the same time.
2. Type in: testing cheats on
3. Press enter.
4. Type into the cheat console: cas.fulleditmode
5. Press escape to exit the cheat console.
6. click on the Sim and select Modify in CAS (short for Create-a-Sim.)
In CAS, you may change your Sims' aspiration, traits, weight, appearance, voice, clothing, marital status, age and clothing, etc.
The Sim does not need to be in your playable household for you to do that.
Therefore, you follow your Surgeon Sim to work, if you would like to check a co-workers' traits, then, you may enter CAS to fix any Sim you want.
You may check your Sims' relationship tab --- under romance --- to see if they have been cheating. If they have, you may go into manage worlds, and trash the cheater Sim. Then, the cheater will cease to exist --- without any messy "kill the bad Sim" plans or fist fights
.