“There is always an easy solution to every human problem – neat, plausible and wrong”
H.L.Mencken

Found in the May 2008 Issue of Harvard Business Review. I think you can easily translate it into something else as well:

“There is always an easy answer to every question about your customers – neat, plausible and wrong”.

If you have ever attended a meeting with managers talking about customers and making “uninformed decisions” without evidence, you know what I am talking about.