Somewhere along the line, Cervantes forgets the name of Sancho's wife. In Part 1 of the book, we see that her name is Juana (22.214.171.124); but throughout Part 2, it's clear that her name is Teresa. Oh, well. We'll chalk that one up to the fact that Cervantes was writing a really, really long book by hand.
Teresa Panza has a lot of hang-ups when it comes to pride and social class. When she first receives a kind letter from her superior, the Duchess, she exclaims, "[W]hat a good lady is this! not a bit of pride in her! Heaven grant me to be buried with such ladies, and not with such proud madams as we have in our town" (126.96.36.199)
On the other hand, Teresa knows her place in the world. For example, she tells her ambitious husband Sancho: "You may go, and be a governor, or an islander, and look as big as bull-beef if you will; but by my grandmother's daughter, neither I nor my girl will budge a foot from our thatched house" (188.8.131.52). Teresa's not going to make a fool of herself by pretending to be from a higher social class than she really is. Unlike Don Quixote and Sancho, Teresa is pretty grounded in everyday reality, and she knows the rules.
The thing is, though, that once Teresa hears that her husband has made good on his tall tales and has actually become a governor, she forgets all her old stories about not wanting to be rich and totally celebrates her new wealth. (So much for being "realistic," huh?)
Just like her husband, Teresa throws out all kinds of proverbs to prove her points. We can just tell from the kind of language that Teresa uses that she and Sancho are a great match. It's also cool to note that some of these proverbs support the idea that the unlikely or the fantastic can actually happen to ordinary people. Teresa, for example, says: "That which is good to give, is good to take, girl. It were a pretty fancy, troth, to lie snoring a-bed, and when good-luck knocks, not to rise and open the door" (184.108.40.206).
When good fortune does actually happen to the Panzas, it just goes to show us that in this novel, there is an element of the fantastic even in the simple, everyday life of poor Spanish peasants.
(Note: Teresa's original name—Juana—appears in some editions as "Joan.")