There was a forum post I read years ago that was a cumulation of screenshots of articles and forum posts where groups of people were completely wrong about things but supremely confident. One of them was this post about smartphones being a total waste of time and that the industry would never recover from such a silly investment. The comments were in total agreement "It'll never work! Imagine how glitchy the touchscreens will be!" lol
It was a giant echo chamber of nonsense, and many of those people probably weren't stupid, but easily influenced by the majority.