This website is explaining why minecraft is the grandest game of all time.
It is infinte so that means you have infinite room which means infinite possibilities.
There are also mobs to fight and there are 2 bosses and 3 boss like mobs.And there are achievements which make the game way more fun and there are like 3 or 4 secret achivments.
That is all not including mods also known as modifications.
This is a link to minecraft