I had that happen with a mystery where the last line revealed the narrator was the killer the whole time. Went back and reread the whole book and all these little comments suddenly made sense. Now I do the same thing you do, read the last bit twice before I put it down. Saves me from missing stuff.

Man, I feel this. Those "in 24 hours" books are written to sell copies, not teach you how to think through a problem, and you paid the price with 60 hours you'll never get back. What was the moment you realized the book itself was broken, like did you catch a specific error in the code that made you stop trusting it?

Curated by industry vets" is just code for copy-pasted, so a $36 lesson in not buying apps at 11pm is honestly cheap.