You shouldn't access an online account that isn't yours.
Tom's roommate Jim has an Amazon Prime account but Tom does not.
Tom wants to watch a movie that's on Amazon Prime Video.
Tom starts a trial Amazon Prime membership so that he can watch the movie.
Without asking Tom goes into Jim's room, finds his password, and logs into his Prime account to watch the movie.
Tom really enjoys watching the film.
Jim comes home and gets angry at Tom for violating his trust and using his account without permission.