In Arthur Miller's Death of a Salesman, what are some examples of and quotes relating to the theme illusion versus reality?

In Death of a Salesman, Willy Loman constantly indulges in illusions rather than face reality. For example, he imagines that his son, Biff, can become a successful salesman if Biff only applies himself. In Act One, Willy says of Biff, "I’ll see him in the morning; I’ll have a nice talk with him. I’ll get him a job selling. He could be big in no time." Willy ignores the reality about Biff, which is that he is happier and more successful as a farmer in the west; instead, Willy clings stubbornly to the idea that the proverbial tomorrow will bring a new and brighter future for Biff that involves his going into sales, the field in which Willy works. 

Part of Willy's illusion is that he lives in the past. He is constantly caught up in remembering days gone by; for example, in Act One, he recalls telling Biff and Happy when they were younger that he wouldn't travel anymore. He says, "Tell you a secret, boys. Don’t breathe it to a soul. Someday I’ll have my own business, and I’ll never have to leave home any more." What he told his sons in this reverie never came true, but Willy keeps revisiting the past in an attempt to protect his illusions and dreams. 

Happy, Willy's younger son, is torn between indulging in illusions like Willy and being more realistic like Biff. Happy literally tries to present the appearance of being happy at all times. He tells his brother Biff in Act One:

"Sometimes I sit in my apartment — all alone. And I think of the rent I’m paying. And it’s crazy. But then, it’s what I always wanted. My own apartment, a car, and plenty of women. And still, goddammit, I’m lonely."

Happy is a relentless womanizer, and he has the illusion that if he only gets to climb one more rung and become a merchandising manager that he'll be happy, but he also senses that, despite climbing up the corporate ladder and dating a lot of women, he feels alienated and lonely. Happy vacillates between the illusion of happiness that will be created from success in business and the reality that he hates his life and might want to join Biff out west. 

Willy's biggest illusion is that he and his sons will reach success just by being liked by others. He tells his brother Ben in Act Two, "It’s who you know and the smile on your face! It’s contacts, Ben, contacts!" Although Willy spends years trying to get others to like him, no one attends his funeral save his family. It's clear that the principles by which he's conducted his life have also been an illusion—not reality.