what does mean by the message ''unplug your socket to save energy'

[s36]

I am using xperia L. Today when I am trying to charge my phone but it is showing me ''unplug your socket to save energy' though it has only 11% charge. Is the message is harmful? If yes, what should I do? thanks in advanced.

[_alexdon_]

Every time you remove the wall charger from your phone,the message tells you to remove also from the wall socket so you save energy.