Why my Facebook profile says I have 155 friends but I'm only seeing 150 when I ran this http://www.peacegig.com/facebook-apps/backup-friends/index.php?zip-request=true I saw unknown person list as Facebook friend I can't even unfriend nor block. What's going on with Facebook?
This is probably people who have deactivated their accounts. They are still your "Friends" although their account is not active.
The reason for this is that When they re-activate their account, their friends are still connected. Otherwise they would have to re-add all of their friends.