Once some monkeys were sitting on a tree. The tree was at such a place where construction of temple was going on.
A carpenter was sawing a huge log to cut it into two parts. Just then the bell rang for lunch break. The carpenter pushed a wedge into the split portion of the half sawed log and went to take his lunch, along with other workers.
When the monkeys saw that there was nobody around, they jumped down from the tree and came near the logs. They began to play with the tools lying there. One of the monkeys went round the half sawed log and sat on top of it. He sat on it with its legs on both sides of the log, whereas its tail dangled through the split portion.
By that time, another monkey tried to move the wedge out of the log with its hands. Suddenly the wedge came out and the split parts of the log firmly snapped shut together crushing the monkey tail in between. The monkey cried in pain and jumped off the log, but his tail was cut off for ever.

Moral of the story-Look before you leap.