Often, it's just boredom. People are not wired for doing nothing. with a long prehistory of precarious existence, people need to be constantly engaged in productive action. Laziness is a sure recipe for extinction. Neither are we wired for the purely cerebral activity that so many of us are now employed in. we are designed to work with our hands, to scan the horizon with our eyes, and walk long miles. So, we fidget, twitch, fiddle and doodle whenever we are forced to sit still and inactive for any period of time.
Doodling is also an outlet for frustrated artistic expression. The arts in our society have become 'spectator sports' reserved for the talented, while the rest of us are too embarrassed to sing (except in the shower), dance (except for some foot-tapping) or draw (except for doodling). These fundamental outlets for creative expression have been stymied by a combination of social pressure (fear of inadequacy) and lack of training (our overfull school curricula leaving little room for the arts, combined with a flawed view of artistic development as innate and not to be 'messed with' by education).
When we are otherwise occupied - on the phone, in a meeting or lecture, writing a list - basically, any moderately engaging mental activity with a pen in our hand the censor in our head can be turned off, and we allow ourselves to express the ideas that are locked in our head. Usually, we have a limited visual vocabulary that we have at our disposal; depending on the age at which our artistic development stalled. Children learn a set of formal symbols: the face, house, sun, moon, flower, tree, bird, fish, and basic geometric shapes that are established in early primary school. They might add more complex forms later but rarely learn observational drawing. In the early teens, when realistic expression and detail become important, children keenly feel an inadequacy in their ability to draw realistically, and stop drawing. People who stopped drawing very early will tend to limit their doodles to repetitive geometric forms and the learned symbols from their childhood. Those that continued drawing in their teens will include more involved patterns and complex symbolic representations, while people who maintained an interest in creative expression may create intricate doodles and complete drawings.
Doodling, And the best thing about it is there is no right or wrong. There is no painting within the lines. There is just you, your pen, and whatever comes to mind to scribble on the paper before you. In this way, my perfectionism doesn’t even come near my work environment and certainly doesn’t ruin the mood when I set to work afterward.
Personally.if I have a something to draw on and a pencil,I can't get bored
Try drawing " Polygons"