My perla was very bad too, she used to hate me and behaved like the cats you see on "My cat from hell" (for those who don't know the program check it out, it's hilarious:
http://www.animalplanet.com/tv-shows/my-cat-from-hell/) but after she turned 12 years old she became a sweetie. And I'm happy I don't have to go to class with my hands and forearms scratched.
I believe that the quality of our pets' life is far more important than the lenght.