A few months ago I was forced to change my UPlay password (Ubisoft gaming platform) for some reason. I discovered their cunning system made it possible to set a new password via the web that their PC client apparently couldn't authenticate with.
To be fair, I did use a character that (after hitting the problem) I discovered was not allowed by their rules, and in that case I expected the system to not let me use it in the first place. I was quite surprised at this state of affairs, and assume the client must be validating passwords for characters that were not allowed so it could fail without actually authenticating.
What made this even more memorable, and annoying, was that after 3 failed requests, the account is locked until 'later' where 'later' is undefined. It's also undefined what happens if you try again before 'later' is reached - is the 'later' period reset? Who knows? Oh, and due to DRM I couldn't play what I wanted to play which is what I actually wanted to do rather than arse about with the UPlay password management system.
Nice work Ubisoft!