To shut down or restart your Ubuntu machine, you click the Power button on the top panel and select the shutdown option which in turn opens another confirmation dialog box where you have to confirm your action of shutting down or restarting your Ubuntu machine. This same confirmation dialog box will also appear whenever you try to log out or lock your Ubuntu machine.

Of course, this feature is there to save you from the unnecessary shutting down and restarting of your Ubuntu machine. But if you have been using Ubuntu for a long time, then accidentally pressing the Shutdown button is pretty rare. That said, apart from being useful, this feature is kind of annoying, as sometimes we may forget to confirm our action due to things like ignorance or workload which in turn leads to unnecessary power consumption. Here is an easy way to turn off the Shutdown and Restart confirmation dialog box in Ubuntu 14.04.

Full article here:
How to Turn Off Shutdown Confirmation Dialog Box in Ubuntu (Make Tech Easier)