"If music be the food of love, play on.
Give me excess of it, that, surfeiting,
The appetite may sicken and so die."
In this now-famous quotation from the first act of the play, Orsino expresses a somewhat twisted understanding of love. Here, he asks to essentially gorge himself with the "food" of love (he is listening to music) so that he becomes so sick he no longer has the capacity to love at all. This is Orsino's way of expressing his despair over his unrequited love for Olivia, but it also suggests that his perception of desire is intimately connected to self-indulgence.
"Diana's lip
Is not more smooth and rubious, thy small pipe
Is as the maiden's organ, shrill and sound,
And all is semblative a woman's part."
When Orsino meets Viola disguised as Cesario, he provides this elaborate and sensual description of Cesario's mouth and voice. It is, of course, a moment of dramatic irony as Orsino compares the page boy to a beautiful woman. This passage showcases how Orsino's interest in Cesario stems from a mixture of masculine and feminine features, suggesting that Cesario's androgyny is what makes "him" so appealing – to both Orsino and Olivia.
"It is the more like to be feigned. I pray you,
keep it in."
When Viola, disguised as Cesario, goes to Olivia to deliver Orsino's love message, she praises it as poetry. Olivia, however, remarks that she does not wish to read it because it is most likely not genuine. Of course, the primary reason Olivia rejects reading Orsino's musings is because she is not interested in him, but she also suggests that carefully crafted writing is likely to be more insincere than something spontaneously composed out of passion.
"Disguise, I see, thou art a wickedness
Wherein the pregnant enemy does much."
When Viola realizes that Olivia is in love with her (as Cesario), she blames her disguise for attracting Olivia and rendering her a "monster" for loving Orsino. This quotation is a subtle moment of dramatic irony, as the audience understands that it is not simply her disguise that has entrapped Olivia but her gentle and kind demeanor as a woman.
"Alas, our frailty is the cause, not we,
For such as we are made of, such we be."
When Viola realizes that Olivia has fallen for her alter ego, Cesario, she blames Olivia's attraction on women's "frailty" or softness. This quotation is an example of verbal irony, however, as none of the female characters in the play actually embody this frailty – Viola is witty and creative, Olivia is determined and persistent, and Maria is manipulative and daring.
"To be Count Malvolio
...Calling my officers about me, in my
branched velvet gown, having come from a daybed,
where I have left Olivia sleeping"
In this quotation, Malvolio fantasizes about a relationship with Olivia. However, it is important to note that his fantasy is not so much about his love for Olivia as it is for his desire for a higher social status. Olivia is almost an afterthought as Malvolio thinks about the power and luxury he would experience as her husband.
"This fellow is wise enough to play the Fool,
And to do that well craves a kind of wit.
He must observe their mood on whom he jests,
The quality of persons, and the time,
And, like the haggard, check at every feather
That comes before his eye. This is a practice
As full of labor as a wise man's art."
In this quotation, Viola praises Feste for his performance as a professional fool. She notes that to be a professional fool is labor, as it takes a deep understanding of people and, ironically, an immense amount of wisdom. On the early modern stage, fools were often revealed to be the wisest characters in the performance, having served in a position of observation and spectacle. In many ways, Feste maintains this reputation and emerges as perhaps the only truly wise character in the play.
"A sentence is
but a chev'ril glove to a good wit. How quickly the
wrong side may be turned outward!"
In this quotation, Feste wittily compares words to a glove, or something that can be turned inside-out easily. This remark is in keeping with the "upside-down" and "inside-out" nature of the historical Twelfth Night festivities. It also suggests how one who works with words (like Shakespeare himself) has the power to manipulate others but also enjoys an immense amount of freedom and fun with this power.
"Blame not this haste of mine. If you mean well,
Now go with me and with this holy man
Into the chantry by. There, before him
And underneath that consecrated roof,
Plight me the full assurance of your faith."
Of course, the primary figure for gender-bending in the play is Viola, who dresses herself as a man for the majority of the narrative. However, Olivia also upends traditional gender roles by boldly asking – in fact, almost demanding – that Sebastian marry her. In proposing to Sebastian, Olivia steps into the conventional male role while also showcasing how unpredictable and all-consuming love can feel.
"Cesario, come,
For so you shall be while you are a man.
But when in other habits you are seen,
Orsino's mistress, and his fancy's queen."
At the end of the play, Viola's identity is revealed and she and Orsino are engaged. However, Orsino continues to refer to Viola as Cesario, and even declares that as long as she is in men's clothing, Cesario will be her identity. This passage reflects the theme of fluidity in gender and sexuality, as it suggests that Orsino is attracted to Viola in part because of her more familiar identity as Cesario.