matias garcia Posted almost 2 years ago What do you think you could be able to achieve if you were to use 100 % of your brain abilities? well, we do need to use most of our brains.even though some of our brain is left over from developement (i think, we only use around 90%?) we still use most of our brain. Even so, one of my friends is a snowboarder and suffered a major head injury. he almost died. about a quarter of his brain had to be removed. now he is fine but he has a chunk missing from him. just goes to show you that people dont need all their brain.