Friends leave like the leaves in Autumn; slowly, inevitably, and softly flowing down to decay amongst the ground and the wind.
But there's always those few stubborn dead ones that somehow stick to the twigs. Remind yourself to keep close to those ones; don't let them fall and they won't let you.
The same could be said for the books who grow legs, yet they're always sneaking out the back door.
Ask yourself who the books who grew legs are. There is no wrong answer, except for one.