"Love" is a term that characters in Twelfth Night like to bandy about, and the play takes them to task for it as it exposes and explores the folly of misdirected desire. Characters that claim to be in the throes of passion are often exposed as self-absorbed, foolish, and/or misguided, as they fall victim to the trappings found in bad love poetry. Twelfth Night, of course, is famous for its consideration of the relationship between erotic desire and gender, as both male and female characters find themselves drawn to the androgynous "Cesario." Even as it steadily works its way toward an ending of sanctioned heterosexual couplings and marriage, the play also examines more overt same-sex desire in the Sebastian/Antonio sub-plot.
In Twelfth Night, love is often aligned with foolishness, injury, and disease, which suggests that the pursuit of romantic relationships is more harmful than good.
Olivia and Orsino's responses to "Cesario" show that men and women can both be attracted to androgynous ("masculine" and "feminine") features in a romantic partner.