Mine is pretty self-explanatory - I doubt that anybody else has come even close to doing as much caving as I have, and for all the complaints about "endless" caves it only took me around 24 hours of playtime to explore the largest cave system that I've ever explored (outside of my mods) - a true monster compared to anything I've seen in 1.7+:
And that is an insignificant fraction of everything that I've explored in one world alone, which includes even larger networks of caves, ravines, and mineshafts (if you want to be technical pretty much the entire world is one network):
(this does not include the most recent areas I've explored or new chunks I generated out to a new base; the world measures more than 6000x6000 blocks)
(the giant cave system is to the right of center near the bottom, where you can also see a railway I just built to a new base)
Even more than four years ago, prior to signing up on these forums, when I first used the name "TheMasterCaver", I had explored this much in the same world, which is also about how much I explored in my most recent world (overall I've spent around twice as much time playing as in my first world with nearly all of my playtime spent playing the same way):
For comparison, this was my most recent (modded) world:
That said, my original Minecraft name was PogomanMaster, which came from my account on Totaljerkface (Happy Wheels, which I have not played for years). This also explains the clothes on my skin, which I have never changed, even to the 1.8+ format (since I do not play those versions and they still accept the old format anyway).