There are two ways to play the game, the efficient way, and the fun way.
I was on a search for coal last night as I had used up the last little bit that I had to make a couple torches, and I had options A and B available to me. At first I decided that I would just mine a little bit in my cave at night and look for some random coal but just digging in one direction. I found a little bit, but really the whole process seemed a little bit tedious, so I thought to myself, "Let's go and see if those outside caves have any coal in them."
There is a small cave just around the corner from my base, so I went and checked it out, and lo and behold there was some coal just inside the cave. But here is where things got tricky, the cave opened up to the outside world in a spot that was generating a bunch of mobs. Not wanting to see my character go up in flames I took the time to wall off the entrance and make a glass tunnel back to my fort for safety, which now thinking about I need to do a little more work with it to make it 100% safe. Anyway in I went now feeling that my backside was secure. Instantly I see mobs moving around in the darkness and the clattering of a skeleton. I withdrew my bow and started firing at the movement in the distance striking a creeper. Behind him was another creeper, and then another. The darkenss of this cave seemed to be crawling with evil. I ventured down the creeper chamber to find that I had cleared it out and put up some torches to keep it that way. At that point I sealed off another passage where I believe the skeleton was hiding. Finally feeling that my back was secured I took the third tunnel mining the coal and iron that I found along the way, and there at the end was a lavafall in the center of a giant chamber, which must have been only a short walk from my outside house. Thankfully when I came upon the chamber I entered on a balcany which allowed me to see below, and I got to see a creeper jump in the lava and get burned up, that was fun. Next time I get on I'll have to go down there and check it out.
My other project was the continued work on my little castle. I finished up the outer walls and added a rampart that ran the entire distance of the wall. Next I dug up a small moat around the front, which I experimented with a little. I think what I'm going to do with the moat is make it so that if a mob falls in they are sent to their death leaving their loot to surface within my castle walls. If I can pull it off that will give me all sorts of goodies for doing nothing.
I realized what is one of the fun things about this game, there isn't a treadmill, it's all about doing what you want to do and enjoying what that is. If I explore it's exciting to see what is next, or what is waiting for me arond the next corner. If I dig the prospect of finding a treasure is there, or maybe a unique waterflow or lava flow, maybe a chest. If I build, it's totally free building to be whatever I want it to be, usually built out of a need. I saw this video yesterday and it reminded me of all of the negatives of WoW. And while I had fun with it, the evils of it are true.