There once lived a Buddhist monk by the name of Great Master Wonhyo(원효대사) in the kingdom of Silla (during the Three Kingdoms period of Korea). At the age of 45, he set out to the country of Tang (modern day China) to further his understanding of Buddhism. During his travel, he decided to rest in front of a grave when night fell. In the middle of the night, he woke up feeling thirsty and searched for a drink. He found a bowl full of water in the complete darkness and drank it quickly to quench his thirst. He thought to himself “How lucky I am, to find a bowl of such sweet water.” and went back to sleep.
When morning came, he checked to see if there was still water in the bowl. He then realised that the bowl was actually a skull, and that the water was stagnant, putrid water that had collected in it. Realising that he drank the vile liquid from the skull, the monk started throwing up. But then, he realised that in the darkness, he drank from the skull with no problem, and even thought that the drink was sweet and refreshing. To quote:
Objects and rules are only born from the mind; a dead mind is no better than a skull. Buddha’s Three Commandments originate from the mind, everything is born from knowledge. What could I ask for more when I have a mind?
Thus, the Great Master Wonhyo understood the way of Ilche Yushimjo (일체유심조/一切唯心造/“The mind is the origin of everything” – the key principle of Hwaumgyung, an important Buddhist text). He turned back and returned to Silla, where he devoted his life to spreading Buddhism to the people.
Any sadness or frustration can be dissipated if you look back on it. Depending on how you see the world, it can be either beautiful or tragic.