Ok, let's take this a little further, looking at it from all angles, fiction, non-fiction, myth, fact, godly intervention, you name it.
There was a man baptized by John named Jesus. This was probably not his name, but it's likely close enough. So, let's say that I believe someone like Jesus existed. Sure. Why not? The historical evidence suggests he did, so I'll accept that. I also accept that this Jesus guy pissed off a lot of people: Romans, Jews, rabbis, provincial governors, etc.
Jesus was your all around trouble maker, a disrupter of the order of things. A radical who made enemies of the powers that be: the conservatives, if you will; those who wanted to keep things just as they always were. So far so good. This rebellious nature of the good man Jesus is why I like the guy. Let's just say, Jesus is my kind of dude.
So, God sends down Jesus, knowing damned well that he is going to stir up some serious shit. Ok, at this point, God is my kind of dude too. After all, the shit back then did need some serious stirring. But, wait! Things go horribly wrong for Jesus. He gets betrayed by one of his loyal followers. The authorities round him up. A mob overrules any chance of a pardon. The guy gets condemned to death. It's a great narrative for a plot, a metaphor of sorts showing that people are always going to reject the interloper, even one who is the son of their god. People bad, hence, they need forgiving.
Now, this is where we have to separate the fact from fiction. In fact-land, nothing in this outcome comes as a surprise to god. So, the whole passion play is an unnecessary exercise in futility. The closest one can come to explaining the why for it is to say god somehow had to experience life as a man to understand him. But, why? God made man. Surely he understands man...well, at least one would hope he does.
Anyway, it makes much more sense as a great tale than it does a documentary.