We all have reasons why we have certain hobbies, enjoy reading as much as possible of particular tech topics or other, as well as being driven towards wanting more knowledge of a skill, or trade.  What is your favorite topic(s) and what is the catalyst from childhood or later that brought you to having the interests that you do?  What keeps your interest and do you feel that you have accomplished as much knowledge on this topic or are always wanting to learn more?

For me, I'm fascinated by the earth sciences.  I particularly like meteorology, followed by  geology and volcanology.  I started my fascination in eighth grade, during science class where the specific unit covered meteorology and all of the various types of stormy weather.  To this day, I love studying the weather, and predicting what we will actually experience especially if stormy weather is in the forecast.  I've taken thousands of photos of classic severe Texas weather as major wall clouds come through and visually seeing super cells nearby while looking simultaneously on local radar. 

Oceanography is another fascination.  I have followed Osearch Shark Tracker from time to time and find it rather interesting to learn where all of the sharks that have been tagged migrate.  Often interesting during the summer or during peak seasons of migration etc.