Well if we must be pedantic............. I normally say, "Bolshy great white rabbits!" The given reply to your second point is, "A punch and a kick for being so quick!"
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 .