You've probably been told off for doodling in the past. Your teacher might have suggested it was indicative of your lack of concentration while your uni flatmate might have complained that you doodled all over his dissertation.
Moral of the story is: nothing good has ever come from your doodles.
Unless your name is Sagaki Keita. The extremely talented young chap has turned his love of cartoonish doodles into an art form, with this set of classic images made up from hundreds of intricate sketches.
You can see more of his work here.