For me its like playing with legos. Just building whatever I feel like. Its also a "turn off your brain and relax" game which I need right now.
My games need a goal. If I feel the need to be creative I jigsaw a bit or crochet... although its a fixed pattern so I guess its not as creative. I doubt I have the insight to create or replicate something in minecraft.
My son neither has, but my daughter does. She makes all kinds of things in Lego Worlds.