I understand for simplicity for the mom and pop that don’t care about file extensions.  I for one always turn them back on.  One because I sometimes need to make a specific file type, example make a registry file, and two it lowers the risk making a stupid mistake and clicking SomeCoolFamilyVideo.m4v when it fact it is SomeCoolFamilyVideo.m4v.exe and now you are dealing with a virus.

In windows 8 is pretty easy to turn on ‘File name extensions’ To do this:

• Open windows explorer
• Click the pointing down carrot on the right side to expand the menu

• Then Click on View
• Place a check on ‘File name extensions’

• All done and you should now see the file extensions.