Have someone on your "Friends" list that you don't want on there? Go to the
Live Journal Console and use
set ban. This will keep the person from being able to "Friend" you.
If you'd rather certain people not see certain posts you make, but don't want to make all your posts
"Friends Only", try
using filters.
If you want people to ask before they "Friend" you, specify this in your User Info so there are no misunderstandings.
Have a nice day.