A chemistry teacher wanted to bring home to the students, the virtue of OBSERVATION. So one day, he takes a beaker containing urine to the class. He invites the class to sample it and report their taste. None in the class accepts his offer. Then the teacher dips his finger in the beaker and licks it saying, “If I can do it, why not you?”
Then some students picked up courage and tasted it.
After a few students have tasted the urine with disgust written all over their faces. The teacher then explained, “Gentlemen, if you had only be OBSERVANT, you would have noticed that I put my fore-finger in the beaker but licked the middle finger.