The post here of which I'm proudest explains why.
He's not an easy character to write, but when an author gets him right, it reminds me why he's one of my favorite characters in all fiction.
Here are a few panels that get him right. They're from Grant Morrison's All Star Superman. In this story, Superman is dying, poisoned by an overdose of solar radiation. He's rushing from crisis to crisis, acutely aware of how little time he has left. This might be his last chance to speak with Lois Lane before he dies. And yet, when he needs to choose, he has to go. Because someone needs him.
I love that last panel.