While we hope you don't set your password to something obvious like '123456' or 'password', we're not going to stop you. Our only rule is that passwords must be at least 6 characters long. Beyond that, this is your account and your password choice is protecting your files, so you can use whatever password you feel is best.

We believe webcomic Randall Munroe with XKCD defined password strength best in his clasic password strength strip.