This might be the explanation for your last bad date.
Dating website OkCupid purposefully set up bad matches to see how people would behave.
The site was unapologetic about the experiments, despite controversy over Facebook's study to test if it could manipulate users' emotions.
"OkCupid doesn't really know what it's doing," wrote OkCupid president Christian Rudder in a blog post Monday.
He said, "If you use the Internet, you're the subject of hundreds of experiments at any given time, on every site. That's how websites work."
In one experiment, the site told pairs they were a 90% match when in fact they were a 30% match. When people were told they are a good match, they were more likely to send each other messages through the site.
To test if its matching algorithm works and goes beyond the power of suggestion, OkCupid also told good matches that they were bad matches. Good matches, even if told they weren't compatible, still connected but not as much as when they knew their actual compatibility.
In another experiment, OkCupid asked users to rate people's looks and personalities based on their profiles. In profiles without text, people tended to rate a better personality with better looks.
"So, your picture is worth that fabled thousand words, but your actual words are worth…almost nothing," Rudder said.
What happens when photos are taken away completely?
For seven hours in January 2013, OkCupid removed all the pictures from the app and found people actually interacted more.
Users were 44% more often to respond to a first message and contact details were exchanged more quickly compared a week prior when photos were available, according to Rudder's post.
But when the photos returned, the conversations of the 2,200 people who were on "blind dates" disappeared.
"The goodness was gone, in fact, worse than gone," Rudder wrote. "It was like we'd turned on the bright lights at the bar at midnight."
OkCupid's experiment is not quite the same as Facebook's, said Rey Junco, a social media researcher at the Berkman Center for Internet and Society at Harvard University, in an interview with ReadWrite.com.
"What could have happened with the Facebook manipulation was that there was a potential for harm," Junco told ReadWrite.com. "The worst thing could have happened [with the OkCupid testing] is people send a few more messages, and maybe you went on a date you didn't like."
But, asks Washington Post's Brian Fung, "If you're lying to your users in an attempt to improve your service, what's the line between A/B testing and fraud?"
Still, not everyone thought it was as innocent as A/B testing. One person tweeted he was deleting his OkCupid account.