If you are from one who is annoyed very much with unwanted candy crush saga requests and unwanted messages than there is good news that Facebook has now enabled feature to block unwanted users or game requests.
How to block unwanted game request on facebook
To block unwanted game requests on facebook go to facebook settings, now click on blocking in left side menu. In next screen you will found some options to block a user or block app invite from any user, block app , block invitations from any users etc. You can choose your option as you needed like if you are getting candy crush saga requests too much, you can block it inside block app and type the name of app like candy crush saga and enter.
You can also unblock certain users or app whenever you required, so next time you receive any game request just block it and live in peace.