So you are not assigned work by anybody? You do not rely on any other person to provide an input to the work you are doing? You do not deliver the work that you complete to anybody? And it is not subsequently used by anybody else for any purpose? Because if you do any of those things, then congratulations, you have to cooperate with other people to do your work.

I did have such a job, yes. No customers, no clients, no end users.

But that is not what I’m saying; I’m saying you can be a disagreeable person on average, but because you work on a team of you, you only need to get along with your boss, who will leave you alone most of the time.