When you see water flowing uphill

The Snake, The Farmer And The Heron
A snake chased by hunters asked a farmer to save it's life. To hide it from its pursuers, the farmer squatted and let the snake crawl into his belly. But when the danger had passed and the farmer asked the snake to come out, the snake refused. It was warm and safe inside. On his way home, the man saw a heron and went up to him and whispered what had happened. The heron told him to squat and strain to eject the snake. When the snake snuck its head out, the heron caught it, pulled it out, and killed it. The farmer was worried that the snake's poison might still be inside him, and the heron told him that the cure for snake poison was to cook and eat six white fowl. "You're a white fowl," said the farmer. "You'll do for a start." He grabbed the heron, put it in a bag and carried it home, where he hung it up while he told his wife what had happened. "I'm surprised at you," said the wife. "The bird does you a kindness, rids you of the evil in your belly, saves your life in fact, yet you catch it and talk of killing it." She immediately released the heron, and it flew away. But on its way, it gouged out her eyes. Moral: When you see water flowing uphill, it means that someone is repaying a kindness.

African Folk Tale

Yahoo Anwers:
"It means you'll never see water flowing uphill so you'll almost never be repaid for kindness. When you offer your kindness to someone, freely offer it up without expectations of returned behaviors or even a thank you."