The passage from Act 3 Scene 4 has the recurring idea of alleged madness. First, Olivia, Maria, Sir Toby and Fabian were all making Malvolio seem crazy and devil-possessed with his snobbery and arrogance. Then, the passage shows Olivia desperately in love, thinking she is like Malvolio--going mad. Lastly, Antonio's friendship to Sebastian ( who was actually Cesario) was introduced. Antonio was made to seem mad from his misdirected loyalty.