Take a look at the historical returns of the stock market. Using the S&P 500 as an index, if you did the same in 2007 riding through 2008 you would have lost 3

Take a look at the historical returns of the stock market. Using the S&P 500 as an index, if you did the same in 2007 riding through 2008 you would have lost 37% of your money. You could very well continue to ride the wave up, but there is a non-zero risk that it all comes crashing back down again, and that needs to be considered in your equation.