BOSTON ( MainStreet) -- Sometimes opportunity knocks. Sometimes it pounds on the door, screaming to be let in.
But life is full of regrets: the date you never took to the big dance, the email never sent, choosing salad when everyone else got steak. For business leaders, a bad choice at the crossroads can cost them a fortune.
M&Ms lost out to Reese's Pieces when Mars Candy didn't grasp why it should be featured in E.T. ABC passed on a little sitcom NBC rode to billions called The Cosby Show.Yahoo! (YHOO - Get Report) almost took over Facebook back in 2006, a move that might have changed its corporate fortunes forever. There was even a handshake agreement between Mark Zuckerberg and Yahoo! CEO Terry Semel for a $1 billion buyout. Then the company tried to back away from that deal, making a counter-offer of $800 million instead. Even though the original billion was back on the table several weeks later, by then the damage was done and Zuckerberg, with enough time for second thoughts, quashed negotiations. In the company's defense, its blundered negotiations were a byproduct of underperforming earnings and a plummeting stock price, and business history is filled with just this sort of shortsightedness and bad timing. The following are five of the business world's biggest missed opportunities: