(MONEY Magazine) – If you lost a pile of cash in last year's tech crash, you can at least hope the experience made you a wiser investor. But it's hard to learn from mistakes if--like the following conspiracy theorists--you convince yourself that the odds were stacked against you all along.

--ARAVIND ADIGA

NASDAQ

THE THEORISTS Investors who thought they were going to retire on the tech boom wonder why the Nasdaq is down 60% from its March 2000 peak.

THE THEORY Alan Greenspan raised interest rates to spite technology stocks. "He's drunk with power," says one participant on the Motley Fool's "Alan Greenspan Conspiracy Theory" discussion board.

MORE LIKELY EXPLANATION No earnings; in some cases, no prospect of earnings

GOLD

[THE THEORISTS] Investors who have repeatedly bet on an imminent gold resurgence wonder why gold still hovers near its 20-year low.

[THE THEORY] A cabal of the world's bankers is suppressing gold prices for personal enrichment and the protection of the U.S. dollar. Central banks, suggests a writer on Gold-Eagle.com, may be "making large amounts of gold available...at unreasonably low rates."

[MORE LIKELY EXPLANATION] Low inflation, relative global stability and sales of gold reserves by the U.K. and other European nations

U.S. DOLLAR

[THE THEORISTS] Currency traders wonder why--despite weakness in the U.S. economy--the euro hasn't gained against the dollar.

[THE THEORY] Some say the Russian mafia is hoarding dollars. Others blame the U.S. Treasury, which, says a post to a Financial Times online forum, is manipulating markets to "preserve the status of the dollar as the world's main currency."

[MORE LIKELY EXPLANATION] The U.S. may have problems, but the rest of the world is no picnic. When investors feel the U.S. is the best place for their money, the dollar is king.