One day, a monk asked his master, “Master, how can I reach enlightenment?” The master replied, “When you are hungry, eat. When you are tired, sleep.” The monk was confused and said, “But that’s what everybody does.” The master smiled and said: “That’s not true. When you’re hungry, you’re thinking about a hundred things. When you’re tired, you worry about a thousand problems. If you want to achieve enlightenment, you must be fully present in every moment of your life .”

Tale attributed to Yunmen Wenyan (Tang dynasty Zen master in China)