The promise of big data finally began to come into focus in 2014. Whether it was being used to dissect consumers' spending habits, their love lives, or their sleeping patterns, the most insightful revelations brought by harnessing big data were the ones that weren't obvious. 

Here are seven big data insights that helped challenge our assumptions.

1. Facebook has the power to control your emotions

A controversial study by Facebook's data scientists proved that altering the content of a user's news feed could affect the emotional tone of that user's status updates. While the parameters of the experiment were actually rather narrow, the use of the phrase "emotional manipulation" caused a nationwide freakout. Because these changes were made without approval from Facebook users, many criticized Facebook for overstepping. "We never meant to upset you," Facebook COO Sheryl Sandberg said, shortly after the findings were published.

2. A woman's bra size is linked to how much she spends

China's largest e-commerce site, Alibaba, culled its massive data on consumer purchases to link a woman's bra size with her spending habits. According to Alibaba's analytics team, women who buy larger-size bras tend to spend more money overall. Inc.'s Zoë Henry questioned the validity of the correlation, but it just goes to show big data's (perhaps misguided) potential.

3. Taking a train is the happiest way to commute to work

For commuters who rely on public transportation, taking an Uber, a Lyft ride, or a good old-fashioned taxicab to work may seem like a welcome luxury. But the data suggests otherwise. The U.K.'s Office for National Statistics revealed that those who commute by train or subway are generally happier than those who take a taxi or a bus.

4. Tokyo is the world's most sleep-deprived city

New York may be known as the city that never sleeps, but big data shows Tokyo actually owns that dubious distinction. Jawbone compiled data from its fitness tracking devices to determine differences in sleep patterns around the world. The data found that Tokyo residents were the most sleep-deprived, clocking in an average of 5 hours and 46 minutes of sleep per night. The laziest? Perhaps the people of Dubai, who were found to stay in bed past 11 a.m.

5. Uber helps reduce the number of DUI arrests

In May, Uber's anecdotal claim that it helps prevent drunk driving was finally proven with statistically significant data. Using Seattle as its case city and San Francisco as a control city, Uber cross-referenced its data with public crime records to reveal that the introduction of the car-hailing app brought a subsequent reduction in DUI arrests of 10 percent.

6. Bros are from Texas, dudes are from California

Using location data from several billion tweets collected by the University of Georgia, forensic linguist Jack Grieve was able to map out where words like dude, bro, and buddy were used most often. Turns out that bro is most used in Texas and nearby states, while buddy tends to be favored by Twitter users in the Midwest. The Southwest was home to the stereotypical surfer term dude, while the more quaint fella was preferred in the Southern states of Mississippi and Louisiana.

7. The dog days of summer are the perfect time for crowdfunding

Kickstarter's big data team recently released information culled from the 3.3 million people who pledged to fund a project in 2014. Over 22,000 projects were successfully funded, with August somewhat surprisingly proving the most fertile month for meeting a funding goal. Kickstarter also revealed that the most popular day of the week to pledge donations was Wednesday and that most backers gave to a project in the early afternoon, between noon and 2 p.m.

8. People with hard lives think more about the devil

Google's chief economist, Hal Varian, offered The New York Times decades of Web search data to see if there were any correlations between where a person lived in America and what he or she searched for. In the "easiest places to live"--for example, Nebraska, Iowa, Wyoming, and the metro areas in the Northeast and West Coast--people searched more for cameras and tech gadgets. In the "hardest places to live," like Kentucky, Arkansas, Maine, New Mexico, and Oregon, people's searches focused more on health problems and ominous religious concepts, like the "antichrist."

9. Walmart is a hotbed of romantic near-misses

In his new book, Dataclysm, author and OkCupid co-founder Christian Rudder compiled data from Craigslist's "missed connections" board to reveal where most of these encounters took place. Overwhelmingly, they took place inside a Walmart. Other popular locations for love (or lust) at first sight include gyms, bars, and Subway.

10. Americans don't want none unless you got buns, hun

If the rise of Kim Kardashian, Jennifer Lopez, and Nicki Minaj wasn't definitive enough, data has now proven that Americans love butts. Pornhub revealed which parts of the world searched for which part of the body: boobs or butts. Nearly all of the Western Hemisphere, save for Canada and Argentina, preferred rear ends. The derriere was also popular in Africa and the Middle East. Europe and most of Asia, however, preferred boobs.