Volatility does not represent risk

Just because a business's stock price goes up and down more than the market, or another company, doesn't mean it's riskier.
Buffett says people who believe this may increase risk by doing stupid things.
What stupid things? Holding assets that don't increase purchasing power.
These would include:
• Cash
• Bonds
• Treasuries
Make sure your assets will meaningfully increase purchasing power over long periods.

Let's elaborate more on that.
Stocks are much more volatile than cash or bonds in the short term but offer much better long-term returns.
There are a million graphs that show this data to be true, here is one such graph.

The reason most people erroneously abuse stock ownership is that stocks are VERY volatile over the short term.
People see stocks in their portfolios go down, and are too myopic to come to the rational conclusion that volatility recedes with time.

Buffett has always understood this illusion of volatility.
Therefore he has bet the majority of his capital on the stock markets continuing to outperform other risk assets.
The sooner you learn to do the same, the more money you'll have down the road!