With only a few days left in the year, it's a good time for investors to look at the stocks they own and decide whether their performance has met expectations. Let's look at three stocks that had an amazing run in 2013 and assess what made it such a great year for each.

Tesla Motors (TSLA 0.14%)

Tesla is in the midst of a critical growth stage. The Silicon Valley-based electric automaker achieved CEO Elon Musk's aim for Tesla to make a profit this year. Tesla unveiled its highly anticipated Model X crossover in 2012, and the car maker is working on building a more affordably priced model. Tesla also plans to expand its Supercharger network of electric car recharging stations across the U.S. over the next several years. Converting solar energy to electricity, the stations allow Tesla customers to charge their cars for free. Stations now stretch between San Diego, Calif., and Vancouver, Canada, in proximities close enough that owners can go on long trips. Tesla's stock is up an electrifying 360% so far this year.

Netflix (NFLX -1.60%)

Netflix sits fat and happy atop the streaming content world these days. This couldn't have been a better year for the California-based company, with its stock up nearly 310% year to date. Original programming has been the name of the game for Netflix, with popular series such as House of Cards and Orange is the New Black. And the company is poised to continue releasing original content for some time to come. Netflix's recent deal with Disney will develop several series based on Marvel comics characters, giving the company more original content to draw broader viewing audiences. It seems as though Netflix's prospects with original programming are only getting better. But more intense competition from streaming video services could hamper Netflix's growth in 2014.

Best Buy (BBY 0.96%)

Best Buy had a rough past several years. First, founder Richard Schulze offered to buy the electronics retailer and take it private. Then Hubert Joly's appointment as the new CEO created more uncertainty. Investors also worried that online shoppers would drive the nail into Best Buy's coffin. To combat that, the store instituted a price-matching policy and adopted smartphone trade-in promotions. So far, the company seems to be striking a balance between profitability and competing with its rivals' discounts. Third-quarter earnings beat expectations, and Joly's turnaround strategy has impressed investors. Without a doubt, Best Buy's 250% year-to-date return is impressive. But even if the turnaround brings Best Buy more market share, it'll have to fight hard to retain it in 2014.