As you walk, surprise! You meet a stranger who is on the ground. You help her as you ask her, "Are you okay?" She didn't answer, and after you helped her, she didn't say thanks. One day you were home alone when suddenly someone knocked at your door.

You can't help but think, "Who is it? Is it the stranger that I helped yesterday?

Are you going to open the door or ignore it? The choice is yours.