I'm as skeptical of this hagiography as you are (though I have no doubt that Bush spent lots of time in meetings looking bored), but it says something about the perception of intelligence in certain quarters of the country. Here Bush as portrayed as having some ultra-honed "common sense" that more than makes up for his lack of knowledge and intellectual curiosity, and in fact allows him to outwit experts in their own areas of expertise.
It must be from this same perception of intelligence that causes Rep. Joe Barton (R-where else?) to make a fool of himself thusly. Here he is playing the part of the Incredible Man with Uncommon Common Sense:
Ouch, right? Not so fast: Barton apparently later tweeted:
"I seemed [sic] to have baffled the Energy Sec with basic question - Where does oil come from?"