"O swear not by the moon...

...the fickle moon, the inconstant moon, that monthly changes in her circle orb, lest that thy love prove likewise variable" R&J A2,Sc2

I marvel at Juliet's insistence that the moon is variable and not to be trusted. Sure it changes and alters during its cycle, but it's still there in some form. Rather like solid friendships and love. They have to change and develop and alter as they progress otherwise they would become stale and fixed.

Bring on the moon I say, I'll swear by her, life is a series of changes, repetitions and tweaks, rather like the moon herself.