With one of my sims, I haven't gotten to the top of the terrible reputation side, but I'm about halfway there, if I remember correctly. He is in the criminal career and has a mischief aspiration, but he is in a large family so I don't give him the attention he deserves.
When I am focusing on him, I always have him use the Rude Introduction on people and I do tend to spam the negative socials when he captures someone in conversation. Right now he has five or six Sims that hate him, and of those, two are sworn enemies. I think he's gotten in fights with three of those Sims, too.