There is a Ted talk that goes over why Doodling should actually be encouraged:
http://www.ted.com/talks/sunni_brown.html
I'm guity of being caught doodling in class. As early as first grade. I still remember one particular day long ago where a teacher noticed me doodling during class. The lecture halted. My notes were confiscated. Then torn up and tossed into the trash. I was horrified.
And yet, to this day, I've never stopped doodling. It's quite soothing. Some of my best works of art started as "just a doodle."