One of the greatest joys in my life is meeting a new person, asking where they are from, and turning their vague answer (e.g. that of a state) to a town mere miles away from their hometown. I can do this for the entire East Coast, the entire West Coast, the South from Louisiana to Georgia, and the Midwest from Illinois to Ohio. I can do something similar for several other countries; for example, my Austrian roommate was surprised to hear that I knew of Wiener Neustadt, to the south of Vienna proper.
Geography is a hobby of mine; it started when my parents put up a world map on the wall following the stairwell to the attic. I made my parents name all the countries and all the capitals and all the flags, and synchronize them in my little mind. I must have bored them, no doubt, but I found it enriching; indeed I learned the bare basics of geopolitics from that map and my parents' explanations, telling me how South Korea was our 'friend' and North Korea was not. From there I went to academic competition and started playing Sporcle regularly, and now I am William & Mary Quizbowl's premier history and geography specialist.
Why geography, beyond the obvious? I don’t know, but it makes understanding where things happen on the news much easier, as does it when trying to navigate on larger scales. It also makes you seem more knowledgeable about the world, for cultural information often seeps into the raw knowledge that you have harnessed. I know a few of the towns between my hometown and my college town, and could hypothetically navigate through a good portion of the country, large swathes of which I have never set foot in.
In learning geography, you eventually get an appreciation for the sheer amount of people in this world. Play enough Sporcle quizzes about cities in China or India, for example, and behold how few metropolises of that size that the United States or Europe can truly boast. For example, Novosibirsk, the third largest metropolitan area in Russia usually does not get onto top 200 metropolitan areas in the world lists, but even smaller Chinese and Indian ones, like Shijiazhuang or Ludhiana, make the list without any issue, for they are truly huge. One is reminded of the map with a circle that covers China, India, Southeast Asia, and Japan with a circle, with more people being inside the circle than outside.
I know that there are a few other geography wonks like me out there in the world; forums and Sporcle can attest to that. I think it's out of a sense of wonderment with the world, combined with the thorough and utter need to know more. It's the all-consuming imperative that rests within your heads, the general affliction of those addicted to discovering things in the nooks and crannies of the internet and of the world. For us, it is done on maps and on geography quizzes and occasionally in university rooms where Quizbowl is held. For us, it is a form of purpose.