Once upon a time there was an extremely wealthy elder whose attendants were eager to please him by paying him all due deference. When he spat, the attendants rubbed it with their feet. Among them was this stupid man who said to himself, "When he spits on the ground, others rub it with their feet, Now I'm going to be the first one to render the service of rubbing it when he spits next time."
So when the Elder was about to cough and spit out, the man kicked up his foot and trod on the elder's mouth. He broke the old man's lips and teeth. To the stupid man, the elderly man said, "What did you do that for?"
The stupid man replied, "Though I would like to serve you, I have always fallen behind others. So I thought by kicking up my foot when you were about to spit out from your mouth, I would be the first to please you."
People have to pick the right time to do the right thing. They will get into trouble otherwise, even using every possible means to achieve a purpose. Therefore, they should know when it is right or wrong time.