" If a 20% or 30% drop in the market value of your equity holdings (such as BPL) is going to produce emotional or financial distress, you should simply avoid common stock type investments. In the words of the poet—Harry Truman—“If you can’t stand the heat, stay out of the kitchen.” It is preferable, of course, to consider the problem before you enter the “kitchen. "

― , Warren Buffett's Ground Rules: Words of Wisdom from the Partnership Letters of the World's Greatest Investor