Don't get me started on Dropbox web app... the worst cluster*uck of an user interface:

- super slow; scrolling often leaves you in a blank space for seconds when it's catching up; elements showing up on the page after you navigate there pushing things away from or under your cursor

- breadcrumbs in the folders sometimes showing, sometimes not

- different directory tree browsers in different parts of the app

- folder settings split between multiple different places. For something you have to go to Admin console, for something you have to go back to normal viewer

- multiple types of flash messages, showing after different actions, often doubling themselves

- actions in dropdown menus for the same thing ordered differently based on where you currently are

I'm so happy that we are migrating away to our own solution