I wouldn't want my sims to have cancer or become disabled but I'm sure someone can create mods like that. I'd like more violence and more diseases but not very serious life threatening ones from real life. It's not fun dealing with a sim that's broke down all the time but sims 4 sims are too happy right now. I like the disease mods from sims 3 and those are way more interesting than just a germs moodlet. I want sims that can get drunk after so many drinks instead of random moodlets but I doubt that will happen.