Thus did I read in an IRC chatroom:
A 1337 hacker and her apprentice were screensharing during a guided hack. The new hacker asked of his teacher, "How do I become root?"
The 1337 sage instructed her student, "Run 'su'."
The student ran 'su' and, when prompted, entered the root password. But as the young hacker did not know the root password, the command failed.
"I am not root," the student lamented.
The 1337 sage then instructed her student, "Run 'sudo su'."
The student did so, but instead of entering the root password as required by 'su' he entered his own password as required by 'sudo'.
The command succeeded.
Encouraged, the young hacker inquired 'whoami' and stdout responded with: "root".
The 1337 hacker smiled at her student and reminded him, "For it was not until you realized that you were already root, that you became root."