Have you ever wondered how emotions were made? Well I do, at least I think I do. Emotions were created for survival purposes; they were meant for human survival. Let me give you an example.
Anger and rage were created to destroy and kill other humans or animals that do something bad that could put someone in danger. Here is another example. When someone steals your personal belongings, do you feel mad and/or distrusting? Well distrust was made so once a human does something that alerts another human's red flags as suspicious, they don't trust them anymore because they could pose a threat to that human.
There are many examples of this. Disgust. If you were to look at rancid meat or moldy cheese you would want to get as far away as possible from it. This is a natural instinct because it could be poisonous or cause a threat. Joy on the other hand was created so that when a human does something phenomenal or good for human survival, their brains release dopamine so it feels good. This could be because the brain is training us to achieve these things more often, thus receiving more dopamine.
By the way dopamine is also released during drugs, addictions, and other things that you can probably imagine. Boredom, on the other hand, is studied by scientists and has been around since long, long ago. What is its purpose? Well boredom could have come to be to get humans to find other activities that stimulate the brain. What that human would be doing at the moment was not stimulating enough for the brain. While under-stimulated, your brain could make itself work more poorly, have less capacity, and make it develop much slower. There is proof of this. Also, if you are bored you would want to do other things. More stimulating probably, yes, that's why your brain is giving you that feeling. It's protecting you from insanity.
Genie, the girl raised by boredom: There was a child who had an abusive father and he locked her in her room. He blacked out the windows since she was born. She was released when someone tipped the authorities what was going on and they rescued her. At the time she was thirteen, she had no knowledge of English, shapes, anything really, except for the objects in her prison. When she was walked out by the police, she barely even knew how to walk. She never even knew English. She had the mental capability of a two year old. I really feel bad for her. But could that happen to you if you are bored too often? Listen to your brain's warnings.
It could save your sanity.
Read about Genie on Wikipedia.