"When someone shows you who they are, believe them; the first time," Dr. Angelou once said.
Even though she wasn't talking about publicly-traded companies or their stocks, this bedrock principle applies to the world of finance, Cramer told investors.
"To put it as bluntly as possible: when a CEO tells you that business is bad, take their word for it!" the host of CNBC's "Mad Money" said. "Don’t try to make excuses. Don’t bend over backwards finding justification so you can keep owning the stock of a company that’s not delivering. Just get the heck out, at least until the smoke clears and you can better assess the damage."
This rule has kept Cramer focused when investing for his charitable trust. Listening to what CEOs and CFOs say via conference calls and interviews is often the "best resource" for investors to get insights on a particular company, he said.
So don't be too cynical. Like the rest of Angelou's quote says, "People know themselves much better than you do. That’s why it’s important to stop expecting them to be something other than who they are."