Curiosity is natural to human beings. Every child starts as a curious being, trying to explore everything he sees, hears and feels. He/She is not limited to thinking in one particular direction, but society forces us to drop off our curiosity at every level.
When you are a kid, adults often see you as annoying for asking random questions which are nothing just your curious nature to know something which you don’t. Schools/Colleges are structured around grades and outcomes so asking out of the box questions is often seen as distracting or disruptive. So everyone eventually learns to focus on one field, rather than exploring everything.
When you grow up and start working, companies expect you to be specialized at a particular area and want outcomes and not questions of your curious mind, so people again learn to suppress curiosity in areas that interests them.
But only a few escape this keeping their curiosity alive. For them learning becomes a habit and not just a means to get a job.
Society rewards specialization and not curiosity.