Imagine you are standing on the 70thfloor of the Empire State Building, staring at the cityscape. Suddenly a man pushes past you, opens the window and announces his intention to jump. You yell out, "Stop! Don't do it!" the six-foot-five figure turns to you and menacingly   says, "Try to stop me and I'll take you with me!" "Umm... No problem, sir. have a good trip. any last words?" "Let me tell you my troubles," he says, "my wife left me, my kids won't talk to me, I lost my job and my pet turtle died, so why should I go on living?" Suddenly you have a flash of inspiration. "Sir, close your eyes for a minute and imagine that you are blind. No colors, no sights of children playing, no fields of flowers, no sunset. Now imagine that suddenly there's a miracle. You open your eyes and your vision is restored! Are you going to jump? Or will you stick around for a week to enjoy the sights?" "I'll stay for a week." "But what happened to all the troubles?" "I guess they're not so bad. I can see!" " _ " If you really appreciate your eyesight, the other pains are insignificant. But if you take it all for granted, then nothing in life will ever truly give you joy. Actually, there are misconceptions on the road to happiness. misconception1: "Once I know the tools for being happy, then it will work like magic." Don't expect the results to come automatically. It is possible to understand how to achieve happiness, yet not put it into practice. In fact, many people actually prefer to be comfortable and unhappy, rather than bear the discomfort of changing their habits. Just as learning any new skill requires effort, you have to be willing to invest serious effort to achieve real happiness. Misconception 2: "if I become content and satisfied with what I have, I'll lose my motivation to achieve more." Now ask someone who is depressed, "Let's go fishing!" "I'm tired. Maybe tomorrow. And anyway, I might rain..." in reality, happy people are energetic and ambitious. There's never enough time to do everything they want to do. Misconception 3: A beautiful Sunday afternoon, you're in the park having a picnic with friends. Suddenly one person complains: "who forgot the forks? It's too hot for volleyball. I want to go home already." When our mood negatively affects others, we recognize we have duty to be happy and not spoil the fun. But what about when we're at home with our family? Or when we go into the office on Monday morning? like an open pit in the middle of the road, a sourpuss  is a public danger. Being happy is part of being considerate to the people around us. The story is placed at the beginning of the passage in order to  _  .
tell a skill of persuasion warn the danger of standing on a tall building emphasize the importance of eyesight introduce the theme of the passage