"so full of shapes is fancy
That it alone is high fantastical...."
See in text (Act I - Scene I)
Orsino muses on love in this opening speech, lamenting its melancholy nature while noting that it manifests itself in different ways, which makes it magical. While dramatic and excessive, this speech not only gives the audience insight into Orsino’s views on love, but it also foreshadows the many "shapes" and disguises that the characters wear during the events of Twelfth Night.
"If it be thus to dream, still let me sleep!..."
See in text (Act IV - Scene I)
Sebastian’s response to Olivia takes on the form of a heroic couplet, popularly used to end a sonnet in order to deliver a moral or a truism. Most importantly, Olivia’s next lines complete Sebastian’s final couplet. Shakespeare would have used this as an indication of these two characters’ future together, because of their ability to speak in harmony.