Sir John Templeton famously said: "Bull markets are born on pessimism, grow on skepticism, mature on optimism and die on euphoria." The financial crisis' deep pessimism and deeper scars kept us in "skepticism" for years. When optimism blossoms, volatility whacks it. As discussed in my July 29 column, after a great 2017, investors spent 2018 fretting Italy, Turkey, tariffs and Trump. Euphoria? Absent. That's giving us this elongated, grinding bull.

The Fed also helped slow stocks with six years of quantitative easing (QE). They called it "stimulus," but it really flattened the yield curve, reducing long-term interest rates while short rates were fixed near zero. As my column on Nov. 5, 2017  explained, banks borrow at short rates, lend at long rates and profit off the spread. A flatter rate spread zaps loan profits, sapping lending. Crawling loan growth slowed the expansion, amplifying fear. To many, the expansion always seemed one sneeze away from dying.

Events abroad conspired against sentiment, too. Britain nearly had a double-dip recession in 2012. The eurozone had a regional bear market in 2011. A second, two-year recession followed. Those woes slowed markets globally. Investors everywhere feared Greece would shatter the euro - and the world economy with it. As a result, we didn't really get synchronized global growth until 2017. History's most joyless bull market has been a grind.

This is also a long bull because neither of the two bull-killers has happened: We haven't climbed Templeton's wall of worry to euphoria. And nothing has walloped stocks in the meantime - no huge, unseen negative capable of knocking a few trillion dollars off world GDP. Just endless biting gnats along the way.

Is there a "who" deserving credit for this bull? In one way the last bear gets the credit, since it depressed investors. You could send a thank-you note to Ben Bernanke and former Treasury secretary Hank Paulson - not for saving anything but for dismantling traditional Wall Street in 2008.

Bernanke and his Fed justify a second thank-you note for being overly cautious and using QE to address "too big to fail" by recapitalizing banks through the back door.