Peppermint Patty is noted for her persistent habit of profoundly misunderstanding basic concepts and ideas that most people would consider obvious, then blindly ignoring any counsel against her latest fixation which leads to ultimately embarrassing situations for which she blames those who warned her. For a long time, she was unaware that
Snoopy was a dog, referring to him as "a funny looking kid with a big nose." This was a recurrent gag in the strip until an incident (featured in a series of strips from March 1974) in which Patty declares she is through with school and plans to spend the rest of her days staying in "Chuck's guest cottage" (Snoopy's dog house). By the end of this story arc,
Marcie angrily informs Peppermint Patty that the "funny looking kid" is actually a beagle, leaving Patty in stunned shock for several strips. In a later phone call to Charlie Brown, Patty finally accepts the truth: "Let's just say my pride had the flu, okay, Chuck?" She also thinks a school for
gifted children means that enrolling will result in her receiving free gifts. She confuses a dog
obedience school with a human private school, going so far as to enroll and graduate with the other dogs. Only later, when she tries to use that diploma to escape having to attend regular school, does she discover that she has publicly humiliated herself for a meaningless honor. Although initially angry with Snoopy, who had recommended the school to her, she forgives him after he rescues her from a fight with a cat named "World War II" (whom she mistook for Snoopy in a cat suit) that lives next door to Charlie Brown. She is widely known for receiving a D− grade on every school assignment or exam (in 1999, the final full year of
Peanuts, her teacher presents her with a certificate naming her to the "D-Minus Hall of Fame"). In one comic strip, Patty gets a Z−, which she calls "sarcasm". In a series of strips in 1984, Peppermint Patty is held back a grade for failing all of her classes—only to be allowed to return to her old class when her old desk in front of Marcie starts to emit snoring noises, leading both students and faculty to suspect that a "snoring ghost" haunts the classroom. Peppermint Patty's bad grades are possibly exacerbated by her tendency to sleep during class due to being too insecure to sleep until her father returns home from working late. In one series of strips, Marcie suggests that Patty's unrequited love for
Charlie Brown (see below) causes her to fall asleep. At Marcie's urging, Patty also goes to a
sleep disorder treatment center to be tested for
narcolepsy; it is reaffirmed that staying up too late at night, and not narcolepsy, causes Patty to sleep in class. Peppermint Patty hires Snoopy twice to serve as her watchdog so she can sleep better at night, but both attempts are unsuccessful. The first time, Snoopy is unable to abandon her waterbed in the guest room to catch the burglars who are stealing from the house, and the second time, a girl poodle distracts him and becomes his fiancée (the engagement is called off on the day of the wedding), leading Patty to angrily call Charlie Brown late at night and order him to come to her house to replace Snoopy as watchdog. Besides guard duties, Peppermint Patty also retains Snoopy's services in other ways, including as an attorney and as a figure skating coach. Her full name, Patricia Reichardt, is first mentioned in the January 15, 1972, strip when she, with Snoopy acting as her attorney, openly challenges the school's new dress code that forbids shorts and sandals. Patty is the most "tomboyish" girl in the comic strip; she is a star athlete, especially in baseball where her team regularly trounces Charlie Brown's. In the first series of strips in which Patty appeared in 1966, she actually joins "Chuck's" team as its new pitcher, relegating Charlie Brown to the outfield. However, she quits in disgust after only one game; despite tossing a no-hitter and slamming five
home runs, her new team loses, 37–5, because of their somewhat porous defense. On another occasion, she lets Charlie Brown throw the last pitch of the game, having pitched a no-hit game leading 50–0, only to see him lose the game 51–50. Peppermint Patty lives with and is particularly close to her father, even though he apparently has to travel a lot. He refers to her as his "rare gem", a nickname Patty loves. No siblings are ever mentioned. She has often lamented her lack of a mother to help her prepare for skating competitions and such: :Peppermint Patty: "Skating mothers are like stage mothers and swimming mothers. They grumble and complain and gossip and fuss, but you really need them!" :Marcie: "How do they get that way, sir?" :Peppermint Patty: "Early rising and too much coffee." Peppermint Patty mentions her mother throughout the television special ''
He's Your Dog, Charlie Brown'', but Schulz repeatedly stated that the situations presented in the cartoon adaptations are not canonical to the strip. Peppermint Patty's mother is the subject of the 2022
Apple TV+ special
Snoopy Presents: To Mom (and Dad), With Love. Unhappy because everyone else has a mother to celebrate Mother's Day with, she decides to celebrate her father instead, because he raised her by himself. == Relationships with other characters ==