There are stupid people in the world, no doubt, and we all do stupid things. But - statistically - speaking:
1) If "an idiot" is someone of subpar intelligence
2) and if "idiocy" is what drives things then
3) We need to redefine "idiot" because we can't all be one.
That's why I like Ariely's books better - he starts with the default notion that if perfectly normal people have these perfectly abnormal reactions, perhaps our idea of "abnormal" needs examination. 'cuz you know what? Human nature is human nature and we're probably a lot better off revising our theories than expecting people to conform to them.
And truth: Dan Ariely starts out his book by explaining that he got started studying people's irrational behavior because as a soldier in the IDF a flare blew up while he was loading it and gave him 3rd degree burns over 70% of his body, so he had an incentive to study pain management - in particular, the idea that ripping off a bandage is better than tugging it slowly. When he needs an example for "buyer's remorse" for his second book he talks about how his doctors told him he should probably ditch the arm because he'll never be able to use it again and it'll hurt like a mutherfucker the rest of his life (and he concedes they were right, but it's not like he can get it amputated now).
Dude is baller. Talks about how "before a mortar shell flayed off my skin I was reasonably attractive. After, I was a horrific burn victim. I had to readjust my romantic expectations. Let's write a chapter about that and then talk about how awesome my wife is."