Hey friends,
Though it's an easy fix it was a bother for some time to me why my battle.net decided not to show my friend lists anymore, it happened a few minor patches back.
I turned on my battle.net to chat with you guys, and... poof, no friends.
So the issue has been identified by blizzard that changed the locale of your battle.net application.
The fix is very very simple, log out of your battle.net application (log out, not close) and change your region to europe and log in.
Voila, fixed
Torm