KidLit Forum

Talk about the dark side from the story, that some call it “Tolkien’s infernal”.

"I suppose you got a fair price for that cup last night?" [Smaug] went on. "Come now, did you? Nothing at all! Well, that's just like [dwarves]. And I suppose they are skulking outside, and your job is to do all the dangerous work and get what you can when I'm not looking – for them? And you will get a fair share? Don't you believe it! If you get off alive, you will be lucky."
Bilbo was now beginning to feel really uncomfortable. Whenever Smaug's roving eye, seeking for him in the shadows, flashed across him, he trembled, and an unaccountable desire seized hold of him to rush out and reveal himself and tell all the truth to Smaug. In fact he was in grievous danger of coming under the dragon-spell. (chapter 12)

I don't know if it fits in here, but the dragon seems to be the image of the cunning devil who knows all your wicknesses and tries to turn them against you. It's not necessarily all about fires and pitch, it's your gun up against your head.
The dragon sows in him the seed of doubt, the worst of all, and makes him feel unconfortable with himself being there all alone facing the pure danger.

You always have to go through hell in order to reach heaven... or not?! Afterall, it's just another step to self awareness:

"Do we really have to go through [Mirkwod]?" groaned the hobbit. "Yes, you do!" said the wizard, "if you want to get to the other side. You must either go through or give up your quest. There are no safe paths in this part of the world." (Chapter 7)