Your password is the only security measure preventing other users from illegally accessing your account. For this reason, it is important that you do NOT share your password with others and that you choose a secure password.
NOTE: The current password guidelines endorsed by UBC Information Security is to use a passphrase rather than a simple password, as it is easier to remember and easier to type on a mobile device (smartphone). This ArsTechnica article gives a good explanation of how to build a great passphrase.
We recommend that different accounts each have unique passwords; this dramatically increases your security (use different usernames if possible, too).