How Dropbox makes customers jump through sales hoops before doing what they actually want.
There should be a fast way to downgrade, whose only confirmation dialogs are ones to prevent accidental mis-clicks or irreversible damage. (Buttons designed to make me feel certain ways will certainly lower my view of Dropbox's classiness, in the same way as a desperate salesman, but as long as I can clearly understand the UI, I haven't been wronged.) If Dropbox wants to try and persuade the user, they can do so after they confirm the user will be downgraded with no further action.