Risk comes from not knowing what you're doing - Warren Buffett

...not doing what we love in the name of greed is very poor management of our lives.

Focus on the Forest — Forget the Trees Investors who evaluate Berkshire sometimes obsess on the details of our many and diverse businesses — our economic “trees,” so to speak. Analysis of that type can be mind-numbing, given that we own a vast array of specimens, ranging from twigs to redwoods. A few of our trees are diseased and unlikely to be around a decade from now. Many others, though, are destined to grow in size and beauty.

You... have to have the knowledge to... make a very general estimate about the value of the underlying businesses. But you do not cut it close. That is what Ben Graham meant by having a margin of safety.