Virtue, how frail it is!
  Friendship how rare!
Love, how it sells poor bliss
  For proud despair!
But we, though soon they fall,
Survive their joy and all
  Which is ours we call.
Whilst skies are blue and bright,
  Whilst flowers are gay,
Whilst eyes that change ere night
  Make glad the day,
Whilst yet the calm hours creep,
Dream though�and from thy sleep
  Then wake to weep.
~Percy Bysshe Shelley, "Mutability"