Humorous dialogue is not a character telling a joke but a line or lines responding to the dramatic situation. Heightened dialogue vs naturalistic dialogue. It serves not only the development of the plot and character, but it also presents the view of the writer. Works well in radio. But there is now a tendency for more naturalism.
Radio producers like to go out on location and explore realism.
In these situations you must stick to natural dialogue. The inner existence. The tension and conflict between the interior and exterior. Easier to explore the real and the surreal and to delineate the line between the two. The interior existence offers exploration of personal thoughts, fantasies, emotions and conflicts.