4. Why can't I tell anyone my password?
Because you don't know where the information will go after it leaves your lips. Even if you only tell one other person, they could tell one other person, and so on, until your password is in the hands of a Cracker (see below). Besides, why do you want to tell someone your password, anyway? You are not allowed to share your username with someone else, so there is no legitimate reason for anybody else to know your password.