During my time practice, one day I suddenly understood the tender smile on the Buddha statue and the good-bye smile from the Zen Masters before their decease. Why in the first discourse at the Deer Park, the Buddha discussed about Dukka (the rendering of suffering and sorrow) and in the last discourse, he often stressed that the sufferings of all beings were indefinite by saying that "the tears of all being are much more than the ocean water," but always had a smile?

• Ignorance is the root of endless lives of sufferings. Humans exist on this earth because of ignorance. That's why they already have a coherence with sufferings since their birth time. But what is the ignorance which can cause so much of sufferings to the people? It is a misperception about humans and other beings. Human body is unreservable, but we still want to hold on. We want to keep things that we can't keep, preservation in place of disintegration, and we misperceive that transiency is eternity, and filthiness is beauty. Even illusion is mistaken to be the truth, impermanent feelings are thought to be everlasting and miserable feelings are thought coming from happiness. The internal illusive mind was mistaken to be the true mind, but the true and eternal mind has been forgotten. We aggressively desire and run after all existences, glamorous scenes, erratic sounds, and temporary tastes. Because of these misperceptions, we will never feel gratified or happy. Instead, we feel disappointed, dissatisfied, and unfortunate. These negative feelings are the root of sufferings. These misperceptions will attach to us forever from this life to the next ones. Therefore, this was described as "the tears of all existences are much more than the ocean water" since they are the cause of the sufferings that can hardly describe.
  
  Even though ignorance is dangerous, if we are enlightened, it will vanish immediately. It is just like a dark house for a thousand years that only needs a light to take away the dark. Ignorance has caused thousand strings of sufferings. It attaches to the people and pulls them into various paths of birth and death (Samsara). It seems that there's no way to escape, but surprisingly, ignorance will vanish when the light of the enlightenment is shown. With a profound understanding of this matter, how could the Buddha not smile?

• Beings are ignorant to fight for sexual desires, money, fame, or self-benefits by fist fighting, degrading, deceiving, and hating each other. They would turn the world into a battlefield. The winners will be applauded or granted with full materials, while the loosers will be despised, oppressed, or starved in poverty. It's so obvious to us that one side is happiness and the other is pain. Thus, whoever exists in this world should be ready at any moment to engage in the battle for a victory. However, not everyone is a winner. If there is a winner, then there is a looser and if there is a happiness, then there is a suffering. Sometimes, not only the looser has to loose his/her life, but the winner is also severely injured. The happiness is so little, while the pains and sufferings are tremendous. Despite the fact, no one would back off for anybody. Vehicle accidents occur daily because no driver is willing to let others pass in order to make it safe for himself/herself or the people. The conflict has become the humans' rule. Well, what will the winner and the looser become? A grave yard or a pinch of ash!
  
  In life, each person is an actor or actress, who is playing in the dramas on the stage. Doesn't matter what role he/she plays, a well known character or a beggar, everything is not real after the show. During the time of disguise, all successes and unsuccesses are merely the games. The bright actor or actress will perform in any type of drama (comedy or tragedy) and smile at the end of the show because he/she knows it is just a game. There is nothing for him/her to worry or regret. The Buddha was fully enlightened to discern the impermanency of life. Of course, when he left this life, he had a tender smile.

• The thoughts in our mind are often mistaken to be the true mind or to be ourselves - I contemplate this way, I think that way, or I am thinking. Because we accepted them to be us, we have given them a chance to cause all kinds of karmas and pull us into the rotation of the Six Paths, where we can't escape. Sometimes, the thoughts aggravate in our brain leaving us no peaceful moment. Since the pleading for peace doesn't work, we have to take tranquilizers to resist them. Even Buddhist monks had to search for a way to "appease the mind" when they were annoyed by aggravations. Some of them, who were afraid of aggravations, had seeked for a "Method of Emancipation." The Great Zen teacher then seriously replied, "Show me your mind so that I can appease it." The Buddhist practitioner was shocked. The enemies disappeared when he looked for them internally. He then answered, "I could not find the mind." With a smile, the teacher said, "I already appeased the mind for you." Instantly, the practitioner saw those enemies apparent like smoke. Because the practitioner sleeplessly worried about the surrounding of annoyances, he had to ask the teacher for the "Method of Emancipation." The Great teacher then taught him by asking "who is restraining you?" The student looked internally, he found nothing there. He then replied, "No one is restraining me." The teacher then smiled and asked, "Then why did you ask for emancipation?" The student immediately realized the vanishing of those thousand strings of annoyances.
  
  When the Buddha had thoroughly understood the illusive characteristic of those aggravating things, he just smiled at them. Whoever still perceives them as himself will be controlled by them. However, by knowing that they are unreal, they can't deceive him/her and their ability for attraction is constrained. The Buddha was able to recognize that the true nature of each person is immense and not subjected to birth and death. Letting go of this unpure and temporary body for a pure, peaceful, and imperishable (Nirvana) body is a pleasant task. Therefore, how could the Buddha not pleasantly smile? Not only him, but many Zen masters and Buddha's disciples had that smile at the last moment of their life. Reverend Phap Loa had left behind a pasean before he died:
  
  

  All elements have terminated a peaceful self
  Forty years plus in a full dream
  Just remember, not to ask
  With the moon and cool wind, there it opens wide

  Carrying this body is carrying a chain, illness, disintegration, pains and sufferings. If we can let go of it, we will feel peaceful and relieved. But that is not the end since there still is a full sky with the moon and cool wind. What else could be better? Thus, the Zen masters smiled.
  
  People in this world sometimes smile or cry. They smile socially, mockingly, seriously, or reluctantly in quiet tears These kinds of smiles subject to impermanent feelings. On the other hand, the smile of the Buddha and the Zen masters, which has no tears, is from the enlightenment and the emancipation (from ignorance). It's called an "Eternal smile." Is there anyone who can courageously say that Buddhism is pessimistic? Buddhism brings the happiness to the people in the present and forever will in the future. We practice Buddhism to terminate ignorance so that we can live in peace forever. It's the purpose of Buddhism in relieve sufferings from sentient beings. A religion that liberates all beings from sufferings is indeed a religion of joy. Because happiness is the result of the end of sufferings, Buddhism is said to be optimistic; More so, it is an eternal optimism.