Yes you are right. I think you can create 12 or 15, but only the top 10 will show. Even if you have no items in them. And if you create key works like men, it will put items in you catergory that have men in the title. Including Women, because it recogizes the letters only not as whole words.
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 .