Sorry for the morbid take, but the reason why we cannot sit quietly alone is to distract ourselves from our eventual demise.
“Distraction is the only thing that consoles us for miseries and yet it is itself the greatest of our miseries.”
I think the aversion I have to being alone with my thoughts is the feeling that doing that won't help me. It's sort of like a neural network that I'd alone with its weights with no inputs to process except itself. I feel when I think to myself alone, I can't make any decisions because what I know is already what I knew before I started thinking to myself. Yo make decisions, I need external answers to questions. I need new information and evidence to start me to some conclusion.
It makes me feel like I need to be kind no matter what, not waste time (or at least, not tell myself that I’m wasting my time too many days in a row).
Background anxiety about our "eventual demise" is the consequence of false entitlement to life and health. Young and healthy people imagine good life without end, the dying and people who've lost health and ability often know better.
This change in perspective also helps you make the most out of each day, because those who make a point to remember that their good days are finite will not want to have spent them in waste.
And will at least think about what this means.
At least, I’m still expecting to someday figure out why mortality isn’t a problem after all (or not mortality in the first place).
When I successfully reproduce, I will stop fearing death.
> Your < reason maybe, not mine or the one of many others. The fear of death is tied to your culture/education, many people aren't anxious when they think about death