See the pink circles? Now,concentrate on the plus symbol...Stare at the plus symbol... Don't look at the pink circles... See what happens... Then look away...and start over...
When you block a person, they can no longer invite you to a private message or post to your profile wall. Replies and comments they make will be collapsed/hidden by default. Finally, you'll never receive email notifications about content they create or likes they designate for your content.
Note: if you proceed, you will no longer be following .