When you start a new job you are given a manual with all of the policies and procedures that help you, in general, function from day to day. When you are born, your brain is basically like those policy and procedure manuals. You have the basics down like breathing, swallowing, keeping your heart beating but the rest of it you have to learn. You have to learn what makes you happy, afraid, anxious, angry, etc. This is evident by the wide array of things that make different people happy. I couldn’t care less about what kind of car I drive as long as it runs and gets good gas mileage. I have friends that spend more on their monthly car payment than their rent, because their vehicle makes them happy.
Infants have very basic needs. They are either hungry, sleepy, scared, cold/wet/uncomfortable, or angry. When a baby cries, he needs to have one of those needs met. Obviously the infant is not thinking through—“Gee, I’m hungry, so let me use my hungry cry.” The infant is likely unaware that he is hungry, or what “hungry” is, but he is uncomfortable and crying makes it stop. In a healthy situation, when the baby cries, the caregiver responds by picking him up to see if he was scared, checking for anything that may have startled him, checking his diaper, and making sure he is not too hot or too cold. If none of those help, they likely try to feed the infant. In this scenario, the infant learns when I have this feeling (hunger) it goes away if I eat. As the infant grows, the parents start pairing language with the action “Awww, are you hungry?” Erik Erickson called this the stage of trust vs. mistrust. The child is learning how to correctly interpret and label his own bodily sensations, and that the parent can be trusted to meet those needs.
Meanwhile, behind the scenes, the body sensed that it was low on energy or nutrients and sent the message to the brain that there was a need. The brain interpreted this as “hunger” and sent out neurotransmitters that caused the sensation of “hunger.” This sensation is intentionally uncomfortable, as lack of food could be a threat. The discomfort motivates a reaction. In the case of the baby, he cried. When the baby ate, not only did the hunger sensation go away, but dopamine (the pleasure chemical) was released, making eating pleasurable, therefore, he wants to do it again. (He learned!)
My point in that scenario is to help you start to see that your brain “makes” you feel emotions, sensations, motivates you and keeps you alive. In order to feel happy, we first have to understand how all of this happens.