These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Is Mala an unreasonable harpy only out to get Vladek's money or a sympathetic character trying to cope with the miserly and demanding Vladek? Vladek certainly subscribes to the former, but Art (and most readers) drift toward the latter.
Vladek is strongly characterized as extremely practical and willing to do anything to survive. He also lists a number of incidents where Jews steal, doublecross or betray one another in desperate circumstances. However, Vladek never admits to a single morally questionable action at the expense of his fellow Jews. One might wonder if Vladek wasn't quite as morally incorruptible as his story makes him seem.
Harvey Pekar of American Splendor fame reviewed the first part of the book for The Comics Journal (December 1986) and questioned what he felt was the overly negative presentation of Vladek by his son, feeling that for all his flaws, Vladek is only trying to show affection in the only way he knows how and criticizes Spiegelman for not making his Author Avatar more flawed, noting that after all the son is putting up with his father solely so he can tell his story to create the book we are reading and is perhaps Not So Different in ruthlessness as compared to his father.
Likewise, Spiegelman himself noted that his own students at art school tend to root for Vladek as a Magnificent Bastard and regarded his Stand-In as a whiny ingrate who doesn't understand how terrible his father's sufferings were.
Crowning Moment of Heartwarming: The family in Hanover that Vladek and Shimek meet after the war. They are given a warm welcome by the German Gentile wife, her Jewish husband whom she hid during the war, and their two children - cat-striped mice. Seeing this obviously loving German-Jewish family unit for a few brief panels is a welcome reprieve after two volumes of cruelty, and serves as a little bit of proof that the Nazi ideology, ultimately, didn't win.
Jerkass Woobie: Vladek is the incarnation of this trope. He's extremely cheap, overbearing, racist and a lousy father. However, he did suffer through immense hardship. He lost his first son and his emotionally fragile wife apparently never recovered from the experience. He's spent decades pining for the family he had before the war.
The point of Vladek is that he, with all his flaws, is powerfully human and not reducible and easily understandable, the fact that Vladek and his son can't bond meaningfully because of Generation Gap and trauma shows the real tragedy of the whole thing.
At Auschwitz, when the bodies were pulled out of the gas chambers, they were pushed into ditches and set on fire. Not all of them were dead. The fires were kept burning longer by recycling the burnt fat of the victims...
The four hanged women. There's a scene in the present that's drawn as if they're hanging there, a sort of flashback.
The comic Art makes about his mother's suicide is this mixed with Tear Jerker.
The cargo trains, packed into in cargo containers without food, water or facilities for days on end.
The countless times Vladek tells of someone who he knew, was friends with, had a plan, etc and after they parted ways they were never seen again.
The ending to the second book (and thus the whole story), one of the most powerful moments of the story, when Vladek slowly goes to sleep and tells Art goodbye... but addresses him as "Richieu", which gives more fuel to Art's previously mentioned feelings that his parents had always loved their dead child more than him. The next and final panel shows Vladek's and Anja's tombstone.
There's also the reunion of Vladek and Anja, which is half sweet beyond words and half heart-wrenching when you realize what happens to Anja later. In spite of that, Vladek's unreliable narration, "We lived happily, happily, happily ever after."
There is a moment near the end where Anja sees the picture of her living husband. Only it was no mouse, it was an ACTUAL photograph of Vladek Spiegelman, a man, a human. It is a simplistic, yet powerful reminder of what the Nazis failed to see, and a reminder that this entire story actually happened.
Near the end, there is a story told to Vladek about a Jew who survived all of the Nazi atrocities and attempted to return to his home, only to find that Poles had taken it for their own and are very unhappy to see the rightful owner return. With no idea what else to do, the Jew sleeps in a room behind the place. The Poles find him there and beat him to death just for the fun of it.
Tough Act to Follow: Art Spiegelman has been quite vocal about how he never expected the "monument to my father" to become so popular, nor did he expect that his later works would be greeted by wishes for Maus III.
What Do You Mean, It's Not for Kids?: Artwork and animals has gotten the comic book to sometimes be mistaken for a something for kids to read. Those kids will pay. Spiegelman expressed the same to Sendak.
Spiegelman: When parents give Maus, my book about Auschwitz, to their little kids, I think itís child abuse.
Despite this, the book is often used in higher forms of middle and high school as a textbook to discuss the Holocaust, both in America and in different countries, especially Europe and Germany who are keen to remind students of their Old Shame.