Why do I need a password anyway?
I don’t have anything important on the computer!
You have your reputation to think about, at least! If someone else gains access to your account, they may cause you a great deal of trouble - perhaps deleting your files, using it to hack other systems, download pornography, or forging e-mail purporting to come from you. Having to explain to a colleague, a friend or your tutor where that material actually came from may be difficult, not to say embarrassing.
It's also important to think of the other people who use the system. Even if you don't keep sensitive information in your account, others do. Allowing unauthorised access via your account may compromise the security of their information. And some kinds of attack are only possible if you already have basic access to the system - so guard your password carefully, and if you think someone else knows it, tell the Service Desk and change it immediately. As an online community, we're only as strong as our weakest link.