People are dumb. And don't know it.

I Will Teach You To Be Rich: The world is not Darwinian:

"There seems to be this belief among a lot of people that the world is rational and that bad ideas won't last long because they'll be extinguished by good ones.

I think this leaves out one big thing: incompetence. And, sometimes, a lack of experience.

You'll hear people say 'That was a stupid commercial' and then some smartass will reply, 'Well, if it didn't sell, it wouldn't be on TV!'

Not true.

Just because something is a bad/ineffective commercial doesn't mean it will be removed anytime. I once worked in a company, for example, that was doing a horrendously bad job marketing--literally spending hundreds of thousands of dollars a month without bringing in more than a FEW clients--and yet the bad idea wasn't extinguished.

Similarly, one of my favorite psychology studies is about how people are not only incompetent, but they don't know they are incompetent. I love the title: Unskilled and Unaware of It: How Difficulties in Recognizing One's Own Incompetence Lead to Inflated Self-Assessments (read it here)."