No matter what he does, every person on earth plays a central role in the history of the world. And normally he doesn't know it.

你的狗叫不了是因为我。

【解释】在狭窄的路上行走，留一点余地让别人走；遇到美味可口的食物，留出三分让给别人吃，这是立身处世最快乐的方法。