It's more like a sloped scale than it is a rigid definition.
The Extrovert / Introvert thing, that is.
Too much solitude will cause a natural decline in mental health, even for the more introverted and reclusive among us in society.
This is because the human brain simply did not evolve to be able to handle solitude well. We're social creatures by nature, which is why we evolved to be able to communicate through speech.
But it's also true that a great deal of unnecessary and overcomplicated conflict can arise from too much social interaction as these variables of other people in our lives are also sentient beings with their own feelings, thoughts and narratives.
For me, I have to find the balance between minimal social interaction so that my brain doesn't slap itself sotospeak, but also not so much social interaction that I completely **** myself out of my own feelings, thoughts and narratives...because that absolutely can and unfortunately often does happen to a great deal of many people in life.