In March, investors feared getting crushed in a further decline. Now all they seem afraid of is missing an even greater rally.The Dow had an uncannily similar 46.5% gain in the 117 days that ended April 9, 1930; it lost almost 51% over the next year. Another 47% upswing in 1971 led to a long, choppy decline of more than 37%.Don't be happy; worry.The market's light has turned yellow. Don't try to run it.