She gives the cat a bath every day and doesn't get clawed to ribbons? The cat is too nice and she has too much time on her hands. Lock all the bathroom doors from pets. The next time she decides to give the cat a bath, she will scream in outrage thinking she is trapped outside the bathroom while carrying the cat, which is might be even more annoying. Make her write a book, practice chess, garden, read skill books, things that Sims almost starve to death before they give it up. If she decides to give the cat a bath anyway, you will hear all about it. It never occurs to my Sims to pick up the dirty laundry blocking them from the refrigerator. A stuck or blocked Sim makes more noise than Jane's Addiction, the early stuff. Make the cat do mean things, like following her around hissing for socialization.
It sounds a bit awful making her squeaky clean cat turn on her for being completely annoying. She can't understand cause and effect, like my stupid horse that I send to his stable to pee that gets to the door, pees, enters or enters, exits, and pees. He comes out of that stable just short of Social Workers. Unlike my idiot horse, I found that ill behaved cats and dogs can be a lot of fun when Rover got stuck in the neighbors horse stall and I had no idea how to get him out. He was starving for two days outside in the fall thunderstorms with a startled horse going in and out and wouldn't sleep because he was too hungry and it was awful. Two days later he was still hanging in there, but not for long, so I tried moving him out and back into the household in Edit Town and it worked!
Rover came back with attitude. He declared the three boys enemies and was no longer friends with the parents. His wishes to do terrible things to the boys had some high points, so I let him do it. Sometimes he would pee on one of the boys getting off the school bus, chaise another one at bedtime without my encouragement, just a few wishes come true. Rover is one of my all time favorite Sims. It never occurred to me to encourage or allow pets to act negatively towards their Sims, until now! [: