system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 How does the brain store our personalities?
gpt
The brain is the most complicated part of the body, so much so that we don't fully understand it, meaning this will be an extreme simplification. 

The brain is divided into different parts that each have a specific task. The back of the brain controls what you see, while the front of the brain controls decision making. These different parts have to communicate with each other using neurotransmitters. The amount and kinds of transmitters in our brains can differ wildly between people. 

Someone who is depressed can lack a certain transmitter that is supposed to tell the rest of the brain that they are supposed to feel happy. Someone who is violent could have extra transmitters that tell the rest of the brain when someone should start fighting. These balances of transmitters is what makes each of us have different personalities.