"There are as many ways to live as there are people on the earth."
This quote serves as the basis for one of the book's most important themes: that people can live drastically different, yet equally fulfilling, lives, and if you go around only immersed in your own, you will live in ignorance. Harriet's spy route allows her to observe the different ways her neighbors live and understand them, so that one day she can choose the lifestyle that best fits her vision for herself. This kind of exposure also allows for a non-judgmental perspective.
"It won't do you a bit of good to know everything if you don't do anything with it."
Ole Golly says this in response to one of Harriet's rants about wanting to be a spy so she can know everything there is to know. At the beginning of the book, Harriet is simply taking down observations and writing what she sees, just for the sake of remembering. This information piles up, and eventually becomes the thing that costs Harriet the respect of her classmates. Soon, Harriet learns that the point of knowing things is to use them in some way, and she begins to do this through her journalism on the Sixth Grade Page.
"Something terrible is going to happen. I know it. Every time I have a bad dream I feel like leaving town. Then I feel something terrible is going to happen. And this is the worst dream I've ever had in my whole life."
Harriet writes this in her journal immediately after having a bad dream about Ole Golly. It is foreshadowing, since she predicts that something terrible is going to happen right before her notebook gets stolen by the children at school during a game of tag.
"Does everybody look that way when they have lost something? I don't mean like losing a flashlight. I mean do people look like that when they have lost?"
Harriet observes Harrison Withers' sorrow after the Health Department comes and takes away his twenty-six cats, who were like family to him. This is a significant moment, because Harrison's loss of his cats parallels Harriet's recent loss of Ole Golly. Harriet does not want to believe that losing something so important could possibly make someone that sad, and she hopes she does not begin to feel that sadness herself.
"The time has come to talk of many things, of shoes, and ships, and sealing wax, of cabbages and kings, and why the sea is boiling hot, and whether pigs have wings!"
Harriet and Ole Golly quote this at each other in one of their final exchanges, the night before Ole Golly leaves for good. The line is a quotation from Lewis Carroll's poem "The Walrus and the Carpenter." It is a great example of the closeness of their relationships; they often quote lines from books and famous writers together, and Ole Golly uses tidbits of wisdom from her reading to give Harriet advice or admonitions. These are the memories of Ole Golly that will stay with Harriet long after she has left.
"This page wishes to retract certain statements printed in a certain notebook by the editor of the Sixth Grade Page which were unfair statements and besides were lies. Anyone who saw these statements is hereby notified that they were lies and that a general apology is offered by the editor of the Sixth Grade Page."
This retraction in the Sixth Grade Page is Harriet's way of apologizing publicly for the hurtful things she wrote in her notebook. In most cases, she does not actually believe they were lies—however, as Ole Golly told her in her letter, sometimes telling small lies (in this case, a lie about having lied) is the best way to preserve important relationships. Harriet's willingness to confess to the wrongness of her actions is a mark of her maturity.
"It makes me feel I don't even know my own child."
Harriet's parents are confused to see her jump up to write so furiously in her notebook in the middle of pretending to be an onion, because they have not been involved enough in her life up to this point to notice this behavior before. When she keeps the contents of her notebook a secret from them, they suddenly realize how distant they are from her, and are unsettled by it.
"I saw that life was going to be dust if I kept it up, always dust, nothing more."
Mr. Waldenstein lived a comfortable, wealthy life as a jewelry business owner, but he soon realized that even with all the material wealth he had, he was never truly happy. This realization was the catalyst that sent him on his quest for simplicity and happiness as a delivery man, and eventually it led him to fall in love with Ole Golly.
"There is more to this thing of love than meets the eye... I think maybe they're all right when they say there are some things I won't know anything about until I'm older."
Harriet, a very practical girl who has always taken pleasure in certainty and rationality, is extremely confused by the idea of love and what it does to a person. She watches Ole Golly act entirely different around Mr. Waldenstein, and cannot pinpoint exactly what love is and what it means. Harriet is beginning to grapple with abstract feelings such as this, which is part of growing up—however, these are things she still is too young to understand.
"Something is definitely happening to me. I am changing. I don't feel like me at all. I don't ever laugh or think anything funny. I just feel mean all over."
Isolation can do strange things to a person, and Harriet, alienated by her angry classmates, begins to transform into a vindictive, hostile girl that bears no resemblance to her former self. Though Harriet wrote some mean things in her diary, she never truly intended to hurt her classmates. Now, frustrated with the way they are treating her, she actually becomes a bully, determined to hurt them because she herself is hurt.
