The S&P 500 is up more than 14% in 2020, as of the market close on Dec. 21. That's a great year for the market average, but some individual stocks have fared far better. Consider plant-based-meat company Beyond Meat (NASDAQ:BYND). The stock is up 83% so far this year, turning a $5,000 investment on Jan. 1 into $9,150 right now.

However, that 83% return for Beyond Meat has been anything but smooth. In March while the market was crashing, Beyond Meat stock was down around 30% from where it started the year. And it's pulled back about 30% from highs reached in October -- in early October, year-to-date returns were around 160%.

Therefore, from a pessimistic perspective, one could accurately say investors have lost around $3,800 since October highs. Should shareholders have sold in October?

A hamburger made with Beyond Burger from Beyond Meat is showcased next to commercial packaging for Beyond Burger.

Image source: Beyond Meat.

Beyond Meat stock's story in 2020 is a reminder that volatility is part of investing. But this shouldn't discourage people like you and me. As investing legend Warren Buffett says, "I would much rather earn a lumpy 15 percent over time than a smooth 12 percent."

Consider this: After just 10 years, a $5,000 investment earning a 15% annualized return would be worth almost $5,000 more than a $5,000 investment earning a 12% annualized return. Therefore, enduring "lumpiness" can be enriching if the long-term trend is good enough. 

Considering Beyond Meat's increasing affordability, its international expansion, and its potential for new products and partners, there could be more upside with Beyond Meat stock in 2021 -- although it will likely continue to be an up-and-down ride.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.