After updating Apple’s OS X to 10.9.3 you may find the /Users directory is hidden. This can be annoying but easy to fix and unhide it again just enter this command into the Terminal:

sudo chflags nohidden /Users

It will ask you for an administrators  password just enter it and the folders should be visible again.

While it may seem like a good idea to hide things in this case it is just a nuisance and of limited security benefit.