The first Noble Truth is the truth of suffering: "all life is suffering." This isn't as pessimistic as it sounds--the Buddha isn't denying that there can be great joy and ecstasy in life. However, he points out that we are constantly enslaved to our reactions to the events in our life--whether positive or negative--in a way that is not only self-deceptive but harmful. If something bad happens to me, I react negatively, with revulsion, and do everything I can to make sure that doesn't happen again. If something good happens to me, I react positively, with attachment, and do everything I can to get more and more of that good thing. On an extreme level, the positive reaction of attachment can build into dangerous addiction. But even on a more moderate level, it represents an attachment to what is fleeting, and so it's bound to end in disappointment...