Except, of course, when it doesn’t, sex makes us happy. Yes, it may cause the release of endorphins, which are known for making people feel good. However, the majority of sexually active women in their 20s and 30s still have at least one story to share about an encounter that left them with a variety of distinctly unfavorable feelings after the initial rush had worn off: from unsatisfied and irritated to vulnerable, weepy, and downright furious.