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.
YMMV: The Lost Symbol
Ending Fatigue: The book reaches its big reveal, then subjects the reader to several additional chapters of dull exposition.
Fridge Logic: It's mentioned that Sato was born in the Manzanar internment camp during World War II, and that because of it she "had never forgotten the horrors of war, or the perils of insufficient military intelligence." The problem with that? If she was born in Manzanar, she would have been THREE when the war was over. It's possible her parents could have told her about it later, but still.
Magnificent Bastard: Mal'akh is easily one of the most cunning and manipulative villains in all of literature.
Nightmare Fuel: It's bad enough that Mal'akh drowns Katherine's assistant and (seemingly) Langdon (one in a tank of ethanol, the other in a coffin filling with water compounded with his claustrophia), but the point-of-view switches to those characters in their last moments submerged and dying. At least we learn Langdon averts death, but he's gonna need some therapy...