The whole belief that 'we only use less than 10% of our brains olol if we use all we'll be genii' is a fallacy.

Does that mean that destroying the other 90% that isn't being used will have no consequences on our brain functions? Of course not. The entire brain is being used, just not all of it at the same time when doing a specific task.

Brain imaging research, often taken to be the proof of this non-scientific myth, clearly shows that they are no areas of the brains that are 'black holes', so to speak - ie. areas that never light up in response to some task. All the neurons that comprise the cortex are active to some degree all the time, even during sleep.