Some people not showing on my facebook friends list?

[865]

I've recently added a few people on Facebook, around 8. Of these 8, 2 of them do not show when I open my friends list. Is there any reason for this and am I able to correct it? Thanks.
*On my profile page it says 851 friends. This is the number I had after I added them, so I know they're still there. I've also seen one of their names on my profile under friends, they just don't appear on the list. If that makes sense.
They will show up when I search for them using my list, but they aren't standardly there.

[Jason]

I don't want to sound mean but they could of deleted you?

[RosyCheeks]

There's two answers.
Either they deleted you from their friends list, or their FaceBook account was deleted.