Minecraft is to my 25-year-old self as Legos were to my 5-year-old self: a time-sucking, mind-bending, and sleep-depriving experience in the simplest of activities. It hits the right tune on the subject of creation: it really does provide building blocks for your imagination.
Minecraft has no real direction, anchoring plot, or specific guidelines. Players are dropped into a world with only the ability to carve out resources from the surrounding land; you're a miner (duh!).