We will inevitably have to endure physical suffering such as pain, sickness, injury, tiredness, old age, and eventually death; and we have to endure psychological suffering like sadness, fear, frustration, disappointment, and depression. It does not follow however that it would always be suffering. There are also positive experiences such as ease, comfort and happiness. The key to understanding life is that it is impermanent and that one must live it to the fullest even though it may be full of hardships because we only have such a short time in this world.
The origin of suffering is attachment to transient things and the ignorance thereof. Transient things do not only include the physical objects that surround us, but also ideas, and -in a greater sense- all objects of our perception. Ignorance is the lack of understanding of how our mind is attached to impermanent things. The reasons for suffering are desire, passion, ardour, pursue of wealth and prestige, striving for fame and popularity, or in short: craving and clinging. Because the objects of our attachment are transient, their loss is inevitable, thus suffering will necessarily follow. Objects of attachment also include the idea of a "self" which is a delusion, because there is no abiding self. What we call "self" is just an imagined entity, and we are merely a part of the ceaseless becoming of the universe.
The cessation of suffering can be attained through the unmaking of sensual craving and conceptual attachment or simply put, by attaining dispassion. All clinging and attchment must be extinguished. This means that suffering can be overcome through human activity, simply by removing the cause of suffering.
This aspect of Buddhism lays out the ways to end suffering. It serves as a practical guideline to ethical and mental development with the goal of freeing the individual from attachments and delusions. It ultimately aims to enable the