When the display goes to sleep due to lack of input or whatever, you have to drag upwards with your mouse to unlock the screen. Like some common dirty frickin' smart phone. Yes! Dragging a window to the top of the screen maximizes the window. FOR GODS SAKE WHY. Double yes!
I will never understand why Ubuntu took a very nice desktop Linux distribution, and fucked it up with all these mobile and tablet centric UI absurdities.
Current users aren't going to abandon it because of these various stupidities. The market they need to capture is the market that wants a look-and-feel-alike product.