It's not easy, of course, to understand how these great people think. I read so many books and articles on Alexander the Great, before I finally see a glimpse of what motivates him: his father. Both admiration and hatred for the father. But still, that's just my conclusion. The real thing, who'd ever know..
On another perspective, both Hitler and Alexader made good leaders. People were afraid of them, maybe, but most of them gladly supported them. Why? I heard leadership is about influence. What made both Hitler and Alexander (plus Genghis Khan, Obama, Cleopatra, you name it) so influential? What made them good leaders? Compassion for their followers? I'm not sure for Hitler, and I'm suspicious not for Napoleon as well. Their great visions? Maybe, but how did they convinced their followers? Ah..so many questions of how and why..
What keeps them going is more complicated. Ambition? Glory? Pride? Greed (like one of my friends said)? A yearn for a change? ..Hatred? Alexander fought on in his war in India when he severly wounded. Achilles (even though he's a mere myth) went to Greek even though it meant he won't live long enought to come back home. Cleopatra's willing to be called Caesar's whore just to keep Egypt safe and strong. And, back to Hilter.. even though he's imprisoned, he kept going on.
Oh, well, I guess it's different for each person, what keeps them going on in their little journey called life.
So.. what keeps YOU going? ;)