Okay, now for specifics.
Highly Educated:
In 2008 I earned a Bachelors degree in Biology with minors in Chmeistry and Spanish. In 2009 I turned that Spanish minor into a Bachelors degree in International Studies. At the time I thought I wanted to become a doctor. Then during the winter of 2009-2010 it became quite clear I was not destined for a life in medicine (story to come in later post), and ended up going to grad school instead of medical school. And so in 2012 I finished a dual Masters program and walked away with Masters degrees in Public Health (MPH) and Healthcare Adminstration (MHA). Thus I have two Masters degrees, two Bachelors degrees, and two Minors--some might call that highly educated.
Idiot:
The main example that comes to mind is the difference between a percent and a degree. I work as a health inspector, and the bulk of my time is spent permitting and inspecting septic systems. One requirement for a septic system is to stay at least 50' back from a slope 35% or greater. I have a device called a clinometer that measures the slope of the ground. For years I've been using this device, and making estimations from experience determining the suitability of a lot. After about three years of determining the slope of the ground, my boss said something that made me realize that a 35% slope is very different from a 35° slope. 35° is quite steep. 35% really isn't. Now, I don't think I ever allowed somebody to build a septic system on too steep of a slope, but I realized my initial estimations of some lots were way off. I was rather ashamed to admit (to my boss no less) that I had never made the connection. Anyway--it is stuff like that where I should not be making such silly mistakes.