Making believe be what you are not is the essence of vulgarity.
 Oliver Wendell Holmes Sr., The Professor at the Breakfast-Table (1860). copy citation

Context

“Because a queen or a duchess wears long robes on great occasions, a maid-of-all-work or a factory-girl thinks she must make herself a nuisance by trailing through the street, picking up and carrying about with her pah!—that's what I call getting vulgarity into your bones and marrow. Making believe be what you are not is the essence of vulgarity. Show over dirt is the one attribute of vulgar people. If any man can walk behind one of these women and see what she rakes up as she goes, and not feel squeamish, he has got a tough stomach. I wouldn't let one of 'em into my room without serving 'em as David served Saul at the cave in the wilderness,—cut off his skirts, Sir!” source