Just read an interesting post on this subject, and it's something I've been guilty of in my writing. When I'm in a situation where my protagonist has no other characters to speak to, and/or speaking aloud to himself would be inappropriate, I have been known to use something like: I need to do this, he thought. Everything rides on this. What is your opinion on this kind of thing? Does narration have to be more realistic, as if I were transcribing the story as I watched it unfold? I do try to stick to "show, don't tell" but sometimes it just seems like the most powerful way to get something across is to let you into the character's thoughts. Without having to remodel a plot to fit around a first-person perspective, that is.
Direct thought is a perfectly legitimate way of showing a character's thoughts. There's also the option of implied thought (I have no idea if that's a real term or not) in third person. When you're dealing with a POV character, it's natural for the narration to reflect the biases of that character and, as a result, show what I call implied thoughts. For example, a woman driving home from work and reflecting...something like: Traffic slowed to a crawl. She sighed and stopped with it. Probably just some jackass on the side of the road. Or some orange signs. But surely nothing legitimate. It would probably open up after thirty long minutes in gridlock, for absolutely no reason. Well, whatever. She turned up the radio; Bob Marley's "Three Little Birds" greeted her. If only she could believe its sentiment. But no, she was much too cynical for that. There was too much at stake for her to just start wishing for good tidings. The threat of losing her daughter was real. Not in her head, not just a hypothetical. Real. Blindly hoping for the best would get her nothing. And she knew that, of course. But admitting it was a lot harder. And on and on. They're not direct thoughts, but the narration is so heavily biased by the POV of the character that the reader implicitly understands that these are the things she's thinking about. Either way works. You just have to determine what makes more sense for your scene/story. What I would advise against, however, is not showing thoughts. Don't leave your narration as just the summary of what's happening on the movie screen version of the story. With written fiction you have the opportunity to get deep into the POV character's head, and that's an invaluable way to draw the reader in and make her/him care about the character. That's essential.
