My favorite:
The Lion, The Witch and the Wardrobe by C.S. Lewis (1950)
“I bought these books to have something nice to read to my grandkids. I had to stop, however, because the books are nothing more than advertisements for “Turkish Delight,” a candy popular in the U.K. The whole point of buying books for my grandkids was to give them a break from advertising, and here (throughout) are ads for this “Turkish Delight”! How much money is this Mr. Lewis getting from the Cadbury’s chocolate company anyway? This man must be laughing to the bank.”
Edited to add my favorite below:
Slaughterhouse-Five by Kurt Vonnegut (1969)
“In the novel, they often speak of a planet called Tralfamadore, where he was displayed in a zoo with a former movie star by the name of Montana Wildhack. I thought that the very concept of a man who was kidnapped by aliens was truly unbelievable and a tad ludicrous. I did not find the idea of aliens kidnapping a human and putting them in a zoo very plausible. While some of the Tralfamadorians’ concept of death and living in a moment would be comforting for a war veteran, I found it relatively odd. I do not believe that an alien can kidnap someone and house them in a zoo for years at a time, while it is only a microsecond on earth. I also do not believe that a person has seven parents.”
