I had once helped a friend of mine run a watermelon stall. I noticed something interesting. Almost every buyer would lift the melon up to their ear,smartly tap it, apparently trying to listen to something. I wondered what they expected to hear. Finally I could no longer hold back my curiosity and made bold to ask a customer--an elderly gentleman--about this. Hearing my question,he roared with laughter. Then he replied in a selfmocking tone."Young lady,I have been doing this for more than fifty years. All I know is that everybody would stare at you as if you were a fool if you just pick up the melon and leave!" Not long after that,my watermelon stall friend unexpectedly sent me an invitation for her wedding,which really surprised me. I asked her, "How come you are seized by a sudden desire to get married? I don't remember ever hearing you mention that yon've got a boyfriend." She answered while counting money,"Everyone has to get married anyway,so it is better to get married sooner than later." I could think of no word to refute her. It seems that everybody is living for everybody else and has forgotten the need of their own heart. It may be safe and save a lot of worries by following others' suit in doing things. The use of We or Us will give one a steady and sure sense of pride. But using the pronoun "I" would often give one a guilty conscience. I find all these things somewhat funny. We have got used to taking cue from  others and follow their suit. In turn,we also take it for granted that we should judge the right and wrong of others by our own standard. As a matter of fact,this massive practice is still wrong though we all follow others' suit like this, but we feel at ease and, _ simply because this is the way of us, and so we can have an easy conscience because this has been practiced by so many people. The writer probably feels that it is   _  .
necessary for the buyer to tap the watermelon foolish of the buyers to buy watermelon without tapping it funny that the buyers will tap the watermelons when buying them wise of the elderly gentleman to tap watermelons before buy them