"You smoke too much, Pippin..." - Meriadoc Brandibuck
The Lord of the Rings by Peter Jackson
Useless to blind our eyes in front of reality, chemistry is everywhere. We're living in an environment populated by chemicals; and from the point of view of our brain, reality is first of all chemical. Neurotransmission, cell signaling, metabolism and homeostasis (the way your body works), medications and substances whether they are legal or illegal (e.g: Prozac, amphetamines, sleeping pills, coffee, sugar, cannabis, LSD, etc...), pollution and toxins, the food you eat, all are chemical. Therefore, knowing how all these chemicals are working is an essential part in our understanding of how the brain itself is working.