Principle of least privilege is a way of keeping you safe while using computers. It helps by only giving you access to the things you need and nothing else, so it makes sure that if someone tries to hack into your computer, they won't be able to do anything because you don't have access to all of the things that would let them do bad things. It's like when your parents tell you not to go in the kitchen because you aren't allowed to use the stove unless they're there to help you.