"Foucault's Pendulum" by Eco deeply impacted how I interacted with ideas. I took it as a parable about the danger of mixing dogmas or untestable hypotheses with crowds, conspiracy theories in that case. Ultimately, probably against Eco's intentions, it left me skeptical and increasingly dissatisfied with of a lot of his peers in continental philosophy.
His view, from this article, that “semiotics is in principle the discipline studying everything which can be used in order to lie” adds an interesting spin on that. Maybe you can lie by crafting an entire belief system, start at the root and people will interpret all incoming contradictory information as falsified. That happens in a few domains.
It's hard to get good antibodies in the system for those kinds of manipulation.