Today, while trying to apply some personalization to my pc, I learned a new hack. So sharing it here, hope it might help some of you.

Origin of the problem: I wanted to hide my administrator account from others. So first as a naive trick, I renamed it to Guest Session and created a standard user with my login name. But very obvious, It was not a good solution. So I looked for a way to re order the user names in login screen, so that the Guest Session I created would not appear in the list on top and will look like a normal guest login. While finding that I came across some posts saying, to hide the user from login screen.

Yeah! that was something I was looking for. So here is the solution in few steps.

1. Hide the user

First make the `user` a system user, so it will get hidden from login screen. 
cd /var/lib/AccountsService/users/
sudo vim user.conf

Here user is the name of the user you want to hide. Now, change following: 

SystemAccount=false
To: 
SystemAccount=true
So, you hid your user. Now How will you login? For that you need a manual login method.

2. Add manual login option 

sudo vim /usr/share/lightdm/lightdm.conf.d/50-ubuntu.conf
add the following line at last, 
greeter-show-manual-login=true

Done.
Now you can reboot the system. You will see there is no login for $USER. Although there will be an option to login manually using username and password. Go for it!