This quote essentially means that the most significant events in investing are the extreme highs ("bubbles") and extreme lows ("busts"). Bubbles refer to periods when the prices of securities or other investments rise so fast and high that they detach from their underlying value. Investors are driven by exuberant optimism, often ignoring fundamentals and buying in the hope of selling at even higher prices.

On the other hand, busts refer to periods when those inflated prices crash, often rapidly and dramatically. This is when the bubble "bursts" and the market corrects itself, sometimes overcorrecting, leading to panic selling and a significant drop in prices.

The quote suggests that these extremes, rather than the steady, moderate growth that might occur in between, are what truly matter in investing. This is because they offer the greatest opportunities for profit (if you can accurately predict them) but also the greatest risks (if you get caught up in them).

Applying this idea to today’s world, it could be seen as a warning against getting swept up in the hype of a booming market, such as the recent surge in cryptocurrency or tech stocks. It suggests the importance of understanding market cycles, recognizing when prices are becoming detached from underlying values, and being prepared for the inevitable correction.

In terms of personal development, this concept could be applied to the idea of maintaining balance and not getting carried away by success or disheartened by failure. Just like market bubbles and busts, personal highs and lows are part of life’s cycle. The key is to remain grounded during the highs and resilient during the lows, learning and growing from each experience.