You know all those times you've vowed to never waste another minute on Facebook?

You're tired of seeing your friends' photos of their kids or their cats. You're tired of the endless parade of selfies. You're definitely tired of the political rants.

That's it. No more. You're done.

But then again, you want to see what people are saying about the big game or you want to post your own selfie from that great night out or the office Christmas party.

Then your resolve dissolves and you're back.

What's that line from The Godfather? "Just when I thought I was out, they pull me back in."

Maybe you won't feel as badly about what may be a social media addiction if you know you're not alone.

Researchers from Cornell University have published a study showing that it's tough to break away from using social networks like Facebook. They found four reasons that some people can't resist going back for more.

"These results show just how difficult daily decisions about social media use can be," said Eric Baumer, an information science and communication researcher at Cornell, in a statement.

The study was based on 5,000 surveys of people who had tried to quit Facebook for at least 99 days and failed. The participants were surveyed on days 33, 66 and 99. The survey aimed to gauge each person's moods and feelings about the social site during what they called "the Facebook detox."

The four factors the Cornell researchers homed in were:

A perceived addiction: People who came into the trial with the idea that Facebook was addictive were more likely to cave in to the allure of returning to the site. One person surveyed wrote, "In the first 10 days, whenever I opened up an Internet browser, my fingers would automatically go to 'f.' "

People who came into the trial with the idea that Facebook was addictive were more likely to cave in to the allure of returning to the site. One person surveyed wrote, "In the first 10 days, whenever I opened up an Internet browser, my fingers would automatically go to 'f.' " Moods: Participants who were in a good mood were less likely to give up and revert back to using Facebook. However, if they were in a bad mood, the appeal of the social site was much stronger.

Participants who were in a good mood were less likely to give up and revert back to using Facebook. However, if they were in a bad mood, the appeal of the social site was much stronger. Why you're using Facebook: The study found that people who felt like they were losing privacy on Facebook were less likely to return to it. However, the majority of people think of the social network as a place to keep up with friends and family, and as a place where they can manage how people perceive them. Those people are more likely to revert back to using Facebook.

The study found that people who felt like they were losing privacy on Facebook were less likely to return to it. However, the majority of people think of the social network as a place to keep up with friends and family, and as a place where they can manage how people perceive them. Those people are more likely to revert back to using Facebook. A lack of other social sites: According to the survey, people who didn't use another social media site, such as Twitter or Instagram, were far more likely to go back to Facebook.

However, the Cornell researchers also found that many of the people who returned to Facebook changed the way they use the site, trimming their friend list, uninstalling the app from their phones or limiting the time they spend on the site.

"Facebook also serves numerous important social functions, in some cases providing the only means for certain groups to keep in touch," Baumer said. "These results highlight the complexities involved in people's ongoing decisions about how to use, or not use, social media."