Dream.
When you are in dream state, does it occur to you that everything was so real? So real that you perceive it as reality? Then you wake up to a realm that can only be recognized by our senses. Our understanding of reality is limited to when something is recognized or translated by our senses, (sight,sound, taste). Colors are real because of what we can see, music became real because of what you can hear. But then when you were dreaming why everything was so real eventhough all your senses are fast asleep? If one of the characteristics of dream is that it is temporary, then understand that living is a temporary state while death is .. Well.. A dead person died longer compared to when he was alive. If reality is something that can be touched or see or listened to, know that your body will become dust. So what is real? "Everyone is asleep. Only when they die they awake." -Prophet Muhammad (peace and blessings upon him and his family)