Thirst

It has been said that Buddhism is essentially a psychology of desire. The second Noble Truth proclaims selfish desire or craving as the cause of all the suffering in life, and its importance in Buddhist thought is evident in the fact that the Buddha uses at least fifteen terms for it. The chief of these is trishna, which literally means "thirst." It is an apt word, for in a tropical country like India, the intense craving for water on a scorching, dry day makes a vivid metaphor for the fiercest of human desires.

Trishna is that force which drives all creatures to seek personal satisfaction of their urges at any cost, even at the expense of others. It is the deadliest and subtlest of snares because its gratification almost always brings a surge of satisfaction, reinforcing the compulsion to act on that desire again. It is only later that the consequences of pursuing self-centered desire begin to burn like coals smoldering under the ashes.

Any action undertaken for personal aggrandizement, any human activity or institution that promotes one person or group at the expense of any other, the Buddha would trace to the root cause of selfish desire. As often, the determining factor is the mental state behind the activity - the motivation of profit, power, pleasure, prestige, possession - even more than the activity itself.

---Eknath Easwaran, in his translation of The Dhammapada---