Loss of focus is what most worries Charlie and me when we contemplate investing in businesses that in general look outstanding. - Warren Buffett

Draw a circle around the businesses you understand and then eliminate those that fail to qualify on the basis of value, good management and limited exposure to hard times. ... Buy into a company because you want to own it, not because you want the stock to go up. ... People have been successful investors because they've stuck with successful companies. Sooner or later the market mirrors the business.

It’s good to learn from your mistakes. It’s better to learn from other people’s mistakes.

Since I entered the business world, conglomerates have enjoyed several periods of extreme popularity, the silliest of which occurred in the late 1960s. The drill for conglomerate CEOs then was simple: By personality, promotion or dubious accounting — and often by all three — these managers drove a fledgling conglomerate’s stock to, say, 20 times earnings and then issued shares as fast as possible to acquire another business selling at ten-or-so times earnings. They immediately applied “pooling” accounting to the acquisition, which — with not a dime’s worth of change in the underlying businesses — automatically increased per-share earnings, and used the rise as proof of managerial genius. They next explained to investors that this sort of talent justified the maintenance, or even the enhancement, of the acquirer’s p/e multiple. And, finally, they promised to endlessly repeat this procedure and thereby create ever-increasing per-share earnings.