With the twists of Gone Girl, the suspense of Before I Go to Sleep and the chill factor of Look Behind You ...Best friends tell you everything; about their kitchen renovation; about their little girl's schooling. How one of them is leaving the other for a younger model. Best friends don't tell lies. They don't take up residence on your couch for weeks. They don't call lawyers. They don't make you choose sides. Best friends don't keep secrets about their past. They don't put you in danger. Best friends don't always stay best friends.