Photography
If you could learn all there is to know about one topic, what would it be?
Music.
Women..................the mysterious species.
Writing
Managing retirement funds.
Biology. I can read for hours about plants and animals and how they evolved, and which animals are the most basal, and how certain plants are related even though they seem really different...it's what I want to study in college.
If there were a subject that was possible to learn ALL there is to know about, it would, by definition, be too finite, and wouldn't merit my interest if there were nothing left to explore.
How to make better shine
Medicine
The person that thinks they know it all,
is a fool.
Nature /science