Image you wake up in a huge factory that you've never been in before. You see thousands of people working away, and all the doors and windows are shut and sealed off.
People work, sleep, and spend all their time inside this factory. In this situation, what would you think to yourself? "Now I'm here I might as well join in with everyone else", or would you think, "How did I get here? What lies outside the factory? Why have I been put here?" This example is like our existence here on earth. We human beings have been thrown into existence without any choice, so questions such as Where did I come from? What am I doing here? and Where am I going after I die? keep popping up in our minds. We forget these basic questions in our daily routines, but ignoring them will not make them go away.