O SON OF MAN!
Should prosperity befall thee, rejoice not, and should abasement come upon thee, grieve not, for both shall pass away and be no more.

~ Baha’u'llah, The Arabic Hidden Words #52

For me, this is a nice reminder that those things that bring us happiness and also those that bring us sadness are short-lived.  The things of this world will be only temporary in our lives.  Eventually we will move on to an afterlife in which splendors beyond our imaginations are in store for us.  This does not mean, however, that we are to ignore the good and bad in this world.  We can still enjoy this life, and indeed, we should.  Having grown up near the beach, I frequently think of the ebb and flow of the tides pulling the sands away from the short.  Whether there is a beautifully intricate sand castle, or the unfortunate remnants of a late-night party, the waves will erase all in a matter of hours.