ecstasy makes your body release more endorphins than you normally would. endorphins are are a natural high, when you do exercise or have sex it releases endorphins, which gives you a natural high. ecstasy is just a much stronger dose.
It just gives you a sense of euphoria/happiness, it doesn't really make you look at girls you usually wouldn't find attractive but it makes you more confident about approaching anyone. it's a feel good drug.