How our behavior would change if there was too much or not enough of the neurotransmitter produced.?

Most of us don't realize the importance of neurotransmitters in our behavior and mental processes. Let's evaluate different neurotransmitters as to how our behavior would change if there was too much or not enough of the neurotransmitter produced.How our behavior would change if there was too much or not enough of the neurotransmitter produced.?
Lets not.How our behavior would change if there was too much or not enough of the neurotransmitter produced.?
There are more than 50 that have been positively identified or possibly suspected as potential candidates. Which ones do you wish to discuss. I know that Acetylcholine and norepinephrine are two major neurotransmitters involved in regulating our physiological responses to exercise.

Serotonin is another one it modulates mood, emotion, sleep and appetite and thus is implicated in the control of numerous behavioral and physiological functions. If you don't produce enough one is depressed or has mood swings, a change in sleep or in appetite. There is so much you can talk about with this. I am not sure if this is exactly what you are looking for.