Imagine that you have an identical clone of yourself living with you. You are identical in every way. You have the same knowledge, you know the same people you even have duplicate bank accounts with the same amount of money. You have the same interests, you do the same things and your dreams are identical. If you want to get into better shape, so does your clone. If you want to find a better job, so does your clone. If you fall in love with a beautiful girl, so will your clone.
Now imagine that one day you are woken up by a strange noise early in the morning. You get out of bed and find your identical clone getting ready to go to the gym. Imagine that you have dinner one evening and you find your clone cooking a healthy meal instead of eating your favourite pizza. You go shopping and you bump into that girl that you like and always wanted to talk to. Your clone pushes you out of the way and goes up to her to say hi. You return home and while you watch TV you find your clone applying for that job you always wanted. You see him getting healthier, smarter, happier every day. He now has more friends, he is dating that girl you have a crush on and he drives your dream car to your dream job. One day he says good bye because he is moving out to his new home. How would you feel about that?