Why do cats attack for no reason?

Answer 1

i have raised many dogs and i do not agree on the thought that dogs attack for no reason unless the dog has a mental problem. However you have to do research on the breed of the dog your raising and find out if its an aggressive one. Some dogs like Golden retriever don't attack unless they were forced to.

Answer 2

there are many reasons why cats may attack sometimes they are playful and think that you are play-fighting with them and so they play-fight back, they may be scared eg. they don't know who the person is or they are in a situation there not familiar with.

It is quite possible there is a reason you just can't figure out what it is.