I don't block someone because I disagree with them, I block them because I think they are disrupting the conversations. It's like sending a loud kid out of the room when the grown ups are trying to talk.
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 .