The best example would be Julius Caesar. When the senate declared him an “enemy of Rome”, Caesar was, to put it mildly, royally screwed. He could either stay where he was and await the legions of his rivals to gather and come to him, crushing him… or he could cross the river Rubicon and face destiny manfully with his chin held high.
To cross the river and enter Rome proper was a major step. Not one to take lightly. Caesar’s hand was forced, in a way. But then again, he was fabulously rich. He had an army that was fiercely loyal to him. he could have left. Ran away to a far corner of the world, and lived out his days as a renegade general, loyal to no one but himself… but it wouldn’t be glorious. It wouldn’t be Roman. Caesar wanted to win, wanted to prove himself worthy one last time. He wanted to seize power. Take charge. So he marched towards Rome, and towards his doom…
Oh, he could have stayed, alright. He could have enjoyed himself in Egypt, as Mark Antony later would. Or in Germania or Gaul, where he would no doubt find allies. There was Africa, and the near- and far east. He had the gold, the men and the skill to carve out his own slice of heaven and hold out till kingdom come. But he didn’t want it. He wanted Rome. And he was willing to lose it all just for a shot at supreme power in the land of his birth.