Do friends' holiday posts on Facebook and Instagram make us miserable?

"Smug git. There you are, grinning from the infinity pool of your Thai resort with a cocktail propped on the edge while I'm jammed into a rush-hour bus on a frigid Friday night."

Extreme maybe, but do we cheer for our Facebook friends, our Instagram buddies when they post those luscious, look-at-me snaps from their holiday?

Academic research suggests it's more often the green-eyed monster that raises its ugly head.

A 2013 study by Germany's Humboldt University and Darmstadt Technical University found that  almost 30 per cent felt more dissatisfied with their lives after a Facebook session.

The greatest cause of resentment was found to be holiday images, responsible for more than half of all those left feeling less happy.

For the happy holidaymaker the motivation for the post might be "Wow, look at the great time I'm having in Costa del Braggadocio," but for the viewer, it casts their own life in a less glamorous light.

The happiness of others is not necessarily infectious, at least not when viewed on an iPhone screen.

Another study by Carnegie Mellon University's Human–Computer Interaction Institute found that passive consumption of your friends' feeds correlate with feelings of loneliness and even depression.

However a much more recent study from the same institute found that "The internet's effect on your well-being depends on how you use it".

Researchers concluded that the more people interacted with their friends online, the less depressed they became.

So maybe "Smug git" is the best reaction to those holiday snaps. With a smiley emoticon, of course.