The question is about the relationship of happiness and knowledge:
So what leads to an objectively better and happier life and what negatives do too much or too little knowledge have?
There are two observations to make up-front:
- It is not so important the quantity of knowledge as its accuracy.
- Being unhappy may be a good thing if it gets one thinking about how to become happy again.
Steven Gundry illustrates the problem of inaccurate knowledge when it comes to health, which influences happiness at the bodily level, in The Plant Paradox. He offers a diet that focuses on removing proteins called lectins. These are found in whole grains which according to other diets are considered healthy. But is the information he provides accurate? Is his healthy diet better than the various other diets that pay no attention to lectins? Accurate knowledge is more important than its quantity.
Being healthy is not an on-off characteristic. Those who do not feel well will likely be searching for knowledge to help them feel better. Those who do feel fine enough may not be so motivated but accept a sub-optimal healthy state as normal until more serious problems materialize.
The same goes for emotional health. If one is subjected to what may appear to be verbal abuse either from one's family, work environment or the media, this may make one unhappy. That criticism is a kind of knowledge. What is important is not how much of it one receives, but whether it is accurate or not. If the criticism is accurate it should lead to making changes whose benefits can be measured by how happy one is after those changes.
In sum, it is not the quantity of knowledge that is important for happiness. Rather it is the accuracy of that knowledge. Being unhappy is a motivator to find a way to return to happiness that may not be present in those who have learned to tolerate a less than optimal state of happiness.
Reference
Gundry, S. R. (2017). The Plant Paradox: The Hidden Dangers in "Healthy" Foods that Cause Disease and Weight Gain. HarperCollins.