The Ribbon is too big. It often looks stupidly redundant (section titles matching action button titles, like Find/Find and Exit/Exit). Icons are overused; it shouldn't be a sin to let "only" a word be the label for something. Mostly it looks like somebody emptied all the drawers onto the top of my desk, forcing me to stare at a pile of junk all day long even though 90% of the time all I need from the pile is my pen.