What makes a person a genius?

I am skeptical of the notion of a "genius."

Perhaps in some fields, like mathematics, one occasionally happens upon a person with built-in cognitive hardware that allows prodigious insight. But I have taught innumerable people over the years, and never come across one who does tremendously well out of sheer talent. I have also had the privilege of knowing some who have made great contributions to human knowledge. I find people who love a subject. I find students who read and read and read and, low and behold, they often write extraordinarily well, too. Success is always allied to work, and work to pleasure in learning, from what I can see.

I read the life of Einstein, or of literary "geniuses," or the works of great philosophers, and I find people who love what they do , and never stop asking questions. I don't find people pre-loaded with some supra-mundane mental giftings.

Maybe I'm wrong. In my own discoveries, what I find most helpful, besides omnivorous reading, is a habit of applied double-edged irony. I see both well-developed in some whom the world counts as geniuses. Others, like Madame Curie, Tom Edison, and Jeff Bezos, are at the right place, and apply themselves industriously over many years.