The Bhagavad Gita - Chapter II

"The downward spiral to one's ruin consists of the following process: Brooding on (or merely thinking about) worldly attractions develops attachments to them. From attachments to sense objects come selfish desires. Thwarted desires cause anger to erupt. From anger arises delusion. This causes confusion of the mind and makes one forget the lessons of experience. Forgotten lessons of experience cloud the reason, which results in loss of discrimination (between Truth and non-Truth, Real and not-Real). Finally, losing the faculty of discrimination makes one veer from life's only purpose, achieving union with the Divinity within. Then, unfortunately, one's life itself is wasted.

"But when you can move about in a world that surrounds you with sense attractions, and yet be free of either attachment or aversion to them, tranquility comes and sits in your heart -- and you are absorbed in the peace and wisdom of the Self within. Serenity, Arjuna, is the point at which all sorrow ends!