I think the most important thing in life is to be happy.

生活是世界上最为罕见的事情。大多数人只是存在，仅此而已。

世界上没有像大城市那样的孤独。

The mind is a temporal sequence of processes.

The world is full of people who have never, since childhood, met an open doorway with an open heart.

Natural experiments are a powerful tool for understanding causal relationships in the real world.

The world is a mirror, and we see in it what we are.