It is thus that the private interests and passions of individuals naturally dispose them to turn their stocks towards the employments which in ordinary cases are most advantageous to the society. But if from this natural preference they should turn too much of it towards those employments, the fall of profit in them and the rise of it in all others immediately dispose them to alter this faulty distribution. Without any intervention of law, therefore, the private interests and passions of men naturally lead them to divide and distribute the stock of every society among all the different employments carried on in it as nearly as possible in the proportion which is most agreeable to the interest of the whole society. - Adam Smith, Wealth of Nations
Quotes are a unique enough medium of expression that I'm interested in viewing quotes that people have found collectable, emotionally impactful, useful, memorable, or otherwise noteworthy - perhaps others are similarly interested. To clarify, these need not be even remotely related to rationality. I'm hijacking the mandates traditionally used for the Rationality Quotes thread, with a few modifications:
Please post any meta discussion in the top-level comment named "Meta".