I have to say, the one Sim that has argued more than any other Sim on her own (even more than Nick Alto and Jared Frio combined), is Imogen Pelly! I'm serious! I played around with her, and even tried to get her ex-boyfriend to schmooze her to see if they could actually get back together, he would do nice things like give her flowers and what not, and every other social menu from his end was "be argued with" or "be yelled at," while I catch Jared and Nick doing those things every so often. I'm thinking her hot headed trait doubles her chances of autonomously picking fights. I should have mentioned that Imogen is also mean spirited.