I don't believe that 'Cats are tough'. Physically, their bones are delicate and fragile, they can easily fracture. Their agility makes folk believe they're super-powerful, but you must handle a cat with care. Also, the cats I've owned (dozens over the sixty years) have mostly been easily offended, scared, needy and nervous. They need understanding and affection, reassurance and gentleness. You should never ever thump, smack or throw a cat, you could hurt it internally or break a bone etc. also frighten it terribly. Actually, on reflection, I wouldn't say that ANY of the types of lovely animals that share our lives are 'tough'. They're usually much smaller than us and vulnerable.