They’re feeding you a lie.

More than half (56%) of millennials say they’ve posted a photo on social media to make it look like they were staying, eating or visiting somewhere more expensive than they actually were, according to a survey of 1,000 people released Tuesday by financial site LearnVest.

One reason they do this is because they’re trying to “create jealousy and make themselves appear more desirable,” especially to a former or current love interest, says Fran Walfish, a Beverly Hills family and relationship psychotherapist and author, and the co-star of “Sex Box” on WE TV. Many also have materialistic values, she adds. Indeed, a 2012 study published in the Journal of Personality and Social Psychology noted that millennials are “focusing more on money, image and fame” than previous generations.

Also see: If you have sex with a rich millennial, expect this power dynamic.

Whatever the reasons, one thing is clear — those kinds of posts are likely to have a negative effect on their social media friends and connections. Most millennials say they feel pressure to keep up with their friend’s spending — and of those, nearly half say that social media posts of friend’s vacations and lifestyles contribute to that pressure, according to data from TD Ameritrade. And a separate survey found that more than one in 10 people admit to buying something like a vacation because they saw it on their friend’s social media.

That may explain why millennials are way more likely than other age groups to go into the red for a vacation: Nearly half (49%) say they would take on debt for a good vaca, compared to just 37% of Gen Xers and 18% of boomers, the LearnVest survey found. That’s a costly move: If you slap $1,000 on your credit card at a 15% interest rate, and just pay the minimum (assuming that’s 4%), it’ll take you about 65 months to repay that debt and cost you more than $1,300 in total.