The opening line of Fahrenheit 451 describes Mon-tag's feelings about his job: "It was a pleasure to burn. ... Initially, Mon-tag is proud to be a fireman. He upholds the law by burning the houses of those who own books, and, of course, he burns the books as well.
One (internal) is from your thoughts or the characters thoughts and the other one (external) is from what is actually happening to or around the character.
