Common sense, or lack thereof...

[Brill]

Why is it that many academically smart individuals are the dumbest people when it comes to things that everyone knows...or can piece together? (I use --everyone-- as a broad term, of course, disregarding those who cannot decipher commonsense)

This summer, I volunteered to help my highschool revarnish the gymnasium (not out of the goodness of my heart, it meant I didn't have to take gym all year!)

Back to the story, this girl -Mable- and I were taking our shifts stripping the paint with (the name eludes me) paint-stripper! (for lack of a better term) There is a concrete strip outside the court floor with a drainage hole for floods. She poors this stripper down into the hole and takes out matches....
I am in no particular mood to see her become the Faceless Wonder , so I yell at her to knock it off.
She threatens to light it SEVERAL times, when I finally go get the superviser.

How in the world can anyone be that stupid?
Anyway, do you know anyone who does brainless things?