The unwritten rule that states that before any man can date a woman, her best friend must approve of him. If the man fails the best friend test, the relationship will either
a) cease to exist
or
b) exist in a miserable state until said best friend finally convinces her friend to dump the man

The best friend test is voided if said best friend steals the man, hence ending not only her best-friendship with the woman in question but also creating a new best friend test with her new best friend.

Confusing? Yes. But perfectly logical.
I failed my last best friend test and hence am single.
by quiggler October 9, 2006
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