So... when I installed the system (Mint 14 Cinnamon), I set my user password as per normal.
I logged in, did various things, used 'su' to edit some config files as root, and had to supply my password to do so.
Then I decided to change my user password, using the User Accounts interface. Logged out, logged back in with the new password, no problems...
...that is, until I tried to use 'su' to edit some config files again. Wouldn't take my password for the root user. It would, however, take my old password. Odd... and the same thing for 'sudo' - won't work with my current password, only with the old one.
Shouldn't those be sync'd up, being as I am the owner/adminstrator/only-friggin'-user on this machine? Am I expecting too much for the GUI to do that when the password is changed on an administrator account?