Feeling a little cranky this morning? Well, your Facebook friends and Twitter feed probably aren't helping.

Turns out your social media networks really do have an impact on your mood. According to the Guardian, researchers crunched more than a billion Facebook updates and discovered that when a friend starts bitching about his miserable job or her blow-out fight with her ex best bud, that has a ripple effect:

"People are not just choosing other people like themselves to associate with, but are actually causing their friends' emotional expressions to change," said James Fowler, professor of medical genetics and political science at the University of California in San Diego.

They reached this conclusion by watching what happened when someone posted from a city where it was raining (which has a documented tendency to make posts more negative). Now, you'd think that would simply remind friends in sunny cities to be grateful for their lovely weather, but nope: "every downbeat post triggered an extra 1.29 more negative posts than normal among people's friends. Every happy post led to an extra 1.75 positive posts among friends."

Lesson: Those links from Upworthy and Viral Nova are better than "ugh so tired of the drama" and "having a rough day y'all" posts.

Photo via Shutterstock.