Ask a room full of strangers what they regret the most, and their answers will all have one thing in common: casual sex. However, sexual regret reveals itself in entirely opposing forms depending on your gender. Women regret the casual sex they have; men regret the casual sex that they pass up.

This astounding revelation came from a comprehensive study of tens of thousands of adults asked about sexual actions or inactions that they later felt sorry for.

Far and away, women were more likely to express regret for sexual actions. Among the long list of actions for which women expressed more regret than men: cheating on a partner; hooking up with a friend, coworker, or ex; having a one-night-stand; or giving it up to someone who sucked in bed.

Men, on the other hand, were much more likely to kick themselves over their sexual inactions.  They lamented the loss of “the one that got away” (from their penis). Among the many filthy things men regret: not cheating on a partner, not screwing someone who’s attractive or who would have been good in bed, passing up sexual opportunities by staying in a bad relationship, or not experimenting more sexually when they had the opportunity.

What is it that makes us regret a casual sexual encounter? And why are women more likely to respond negatively to their own self-indulgent sexcapades? When society has questions about sex and psychology, science has the answers.

In a study of over 750 adults in Norway and the U.S., a number of factors influenced subsequent regret about sleeping with some insignificant other, including feeling pressured to have sex, how much they initiated the encounter, their partner’s sexual competence, or whether they got their share of sexual gratification.

The study found the same pattern of greater sexual regret in women, and identified their main reasons for remorse as feeling a sense of worry or anxiety, experiencing disgust (physically or morally), or feeling pressured into the encounter.

On the contrary, ladies were less likely to regret their bootycalls when they experienced higher levels of sexual gratification, had a partner with sexual competence, or when they were the one who initiated the hookup.

Unfortunately, those stars don’t seem to align for women very often. In the study, women tended to describe their most recent casual sexual experience as far less rewarding than men did. They were less likely to initiate the encounter, felt more pressured, thought their partners were less competent, felt less physically satisfied, and were more worried about the potential implications for their sexual health and reputation.

This research sheds light on the shit-ton of hang-ups that women have to tackle if they can ever hope to transform their experiences with casual sex. Of course, men can contribute to a positive experience by being less forceful, letting the ladies initiate sexual encounters, and learning their way around a clitoris. However, the mental anguish that many women suffer following a casual sexual encounter seems to be a largely self-inflicted wound.

Understanding our own sexual psychology allows us to better recognize the barriers preventing us from mutually pleasurable hook-ups. Only when we can overcome the gendered differences in the narratives surrounding our uninhibited humpings can we make casual sex great again.