Graham explained that it's important to ignore Mr. Market and make buy and sell decisions based on value. This can be difficult to do because it's easy to get caught up in the market's reaction. But both Graham and Buffett achieved success by ignoring the market swings and focusing on value.

Sometimes, Mr. Market's judgment is entirely rational. Selling may seem to come from nowhere and be extreme, but it may actually be the right response. This is especially true during earnings season.