Throughout the Sims series' I have avoided certain traits, mean, evil, unflirty, klepto, glutton, slob. Most of the traits, imo, don't do much except bring on tense moods if your sim doesn't do them enough. But, I have tested some of the more nasty ones and I have found I love the mean trait. :D I have a sim who is mean and also a spellcaster. Those sims he hates, if he gets into an argument he will zipzap them, lol. I love it! I have big plans for him. :D
Lesson being, don't poopoo a trait because it sounds like no fun, it just might surprise you. Some I just refuse to give my sim, glutton (hate the way they eat), unflirty (even a friendly hug is too much for these sims), slob (nope, for obvious reasons) and hates children (for obvious reasons).