Friends List

From Metroid - Wiki on Neoseeker

The Friends List contains a list of the peoples whose Friend Code you added. You may play on wireless or online with these friends while also using voice communication, via the microphone, or chat, with the "keypad".

FARG (Friend and Rival Glitch)

FARG is a common glitch found in most game cards that goes into effect when you add more than thirty friends. Keep in mind that the number is not always 30, but this is the common amount. When FARG is in effect, you will not be able to see all of the new friends that you have added after that special number, which again is usually thirty. To remedy this problem, you could clear out all of the friends and rivals that you do not play with, greatly reducing your glitch. You could also erase your game data and start over, but this should be kept to a last resort.