What are the negative aspects of Greece's geography?

The negative aspects of Greece's geography are the mountains, the river valleys, and the thinness of the soil.  Speaking of the mountains, for example, take a simple handkerchief and lay it open on a table.  Then pick it up, and make sure you crumple it in your fist.  Next, straighten it out as much you can on the same table.  That will give you an idea of what the mountains are like in Greece.  There is no orderly march of ranges as in other parts of the world, but a wild jumble of giant dragon's teeth, so to speak. More important, however, is the very small amount of arable land.  The mountains don't provide it and neither do the river valleys with thin, rocky soil and shallow, narrow rivers.

The advantages Greece has enjoyed flow from easy access to the sea, and of course, the imagination, ingenuity, and courage of its people.