Krishna says meditate and you'll see the various ephemeral worlds, the various ephemeral beings, all of them going through the same thing; some are rich, some are poor, some are more knowledgeable, some are less knowledgeable - in countless myriad universes, forever.
There is never a rational reason for a man to rejoice that a certain pretty girl exists and that he has found her. The experience, however, is universal.