EXIT Out of TELNET

Look !   I like linux but what the HECK is this Command.

"CTRL  +  ] "

My telnet session was locked (ctrl+D ,  exit, quit ,ctrl+c) did not work and when i googled it  i found out that the only way i could get out of the session was by using the command above.

This is the weirdest command i have ever seen for something that simple.