Join Fool.com editors Eric Bleeker, Ilan Moscovitz, and Jim Mueller in a live chat about today's crazy market. Just scroll down to post a question.

And this is why we at The Motley Fool believe in focusing on the long term. This afternoon, the Dow Jones Industrial Average dropped nearly 1,000 points -- the single worst intraday loss in its history -- before quickly climbing back up 600 points in one 20-minute span.

For the day, the Dow finished off "just" 3.2%.

The initial thought (aided by CNBC's coverage of riotous protestors clashing with police) was debt-plagued Greece, which has had the market petrified. But later reports suggest something far more ridiculous -- a trading error. Blue-chip stalwart Procter & Gamble (NYSE: PG), for instance, fell from about $60 a share to around $40 a share in a matter of minutes, only to rocket back up and finish back around $60. The Wall Street Journal reported that Accenture (NYSE: ACN) dropped to $0.01 a share!

Now, Greece surely has its problems and contributed to some selling today. But today is a clear picture of why being a long-term, business-focused investor is so wise -- because the daily machinations of the market often have little to do with the value of a business.

Fool.com editors Eric Bleeker, Ilan Moscovitz, and Jim Mueller are hosting a live chat until 5:30 p.m. ET to talk about today's crazy market. Commiserate by posting a comment below:

P&G is an Inside Value and Income Investor recommendation, as well as a Fool holding. Accenture is an Inside Value pick, too. The Motley Fool has a disclosure policy.