cats are timid and afraid of things, many times attack humans for self-defense, but there are also some cats are born with bad temper, which requires the training of our acquired owners, so that cats become more reasonable, so what should we do in the face of bad temper cats?
first, the cat's temper
some cats give warnings before they get angry, such as a low growl, a sharp flick of the tail, or a fluttering of the skin. but some cats will attack suddenly without warning. in short, you have to know if the cat you are holding is the kind of cat with aggressive tendencies. 
confusingly, some cats will suddenly attack (bite) when they are being caressed. this cat sits on your lap a minute ago and enjoys your touch, then suddenly turns its head and takes a bite at your hand! the cat's aggressive behavior is because of her fear. speaking softly to the cat and moving slowly will help ease this mood.
second, how to correct the bad temper of the cat
1, if it is a lonely old cat, may wish to add a kitten to accompany it. because it is easier to accept each other, but it should be noted that kittens are taken home by someone that the old cat never knows. this person appears in the hope that the old cat will not associate you with the kitten and become jealous.
2, if the cat is particularly nervous about someone, you may wish to say that the person is a cat person, such as "this is the cat's lily, it is lily's cat." bring them together. this will dispel the tension and anxiety in the cat's heart, but it should be practiced repeatedly. 
3, the cat is very susceptible to the owner's emotions, as the owner of you should do more stress-reducing exercises and activities, so that you and the cat are relaxed.
4, when the cat feels nervous, it will naturally use its claws to attack its enemies, so you should often cut the cat's nails, when cutting, it is best to hold it by another person to divert its attention. 
in general, the cat does not take the initiative to attack the owner, mostly when threatened or frightened, the cat will have a counterattack behavior, so in life, try not to do something that affects the cat's mood, so as not to cause accidents.