Anyone who reads a lot of fiction will be familiar with italicized font, and what it signifies: internal dialogue or thoughts. This is a very common tool used in first- or third-person close points of view, and it helps bring the reader more intimately into touch with the character’s identity and personality. After all, people can very easily say one thing while thinking another.
This, when used judiciously, can be very effective in making your stories deeper, your characters more fleshed-out. When I think about the ways that Robert Jordan used thoughts to demonstrate Mat Cauthon’s recalcitrance despite his overt heroism, or how Scott Lynch cleverly hints at plot details in Locke’s thoughts while not quite giving it away, it’s very clear that this can be an incredibly effective tool for enriching a story.