BFF, during a sport's season, lets use soccer for instance.
They upload pics, post statuses, become relatives on facebook and hang out . Then season's over, they hand in their uniforms, and hand in all that love you forever crap with it. And suddenly one person is " awfully busy" and can no longer chill. That person is usually the mini hitler, to the friends of the person who actually believed they would be BFF.
Dude 1 : Yo since when does Vivianne hang out with that
white-ass girl Nicky?
Dude 2 : Yo Vivianne, is brazilian you know she's only dealing with that hannah montana shit till seasons over.
Dude 1 : a case of BFFDTS?
Dude 2 : yes, a mild one tho, they never got married on facebook.
BEST FRIENDS FOR AS LONG AS POSSIBLE--- two people who go to eachother for everything and sit at starbucks together with nothing in particular to talk about and play phase 10 and eat applebees everyday. They are the two people you expect to see together all the time and when you see one, you automatically assume the other is around somewhere.