Legal principles that are almost right are often more mischievous than those that are completely wrong. What is transparently wrong is interpreted narrowly (or ignored altogether) and is likely to be repealed. An almost-right principle invites sloppy thinking, vague generalities, and a general distortion of the otherwise sound ideas that lie close by. An example of an almost-right principle that has distorted much of the thinking about corporate law in recent decades is the oft-repeated maxim that directors of a corporation owe a fiduciary duty to the shareholders...