Takes a lot of work to know what you don't know. Often you don't know any of it until you've studied the field a bit. Then you start to get a glimpse of what it is you don't know.

Parallel to that, though, is a habit of constant skepticism regarding your own level of knowledge: and, as well, of your own perceptions. But the latter comes with experience as well. A little work in audio will inform you in most remarkable ways about how much your own ears are "lying" to you (equal loudness contours, Haas effect, masking tones.......) Same can be said for visual art and visual illusions, photography and the perception of color....

__________________
"You keep using that word. I do not think it means what you think it means."