Mullah Nasrudin was standing on the bank of a river, and watched as a dog came to drink.
The dog saw its reflection in the water and immediately began barking at it.
It barked until it was foaming at the mouth, and exhausted, fell into the river -
whereupon it quenched its thirst, climbed out, and happily walked away.
Nasrudin said,
"Thus I realized all my life I have been barking at my own reflection."

 - Sufi teaching story