I don’t know about you, but I find it challenging to preach on non-narrative texts. It’s easy to make a good story from the Gospels or the Old Testament come alive in a sermon. It’s a lot harder to do that with a theological treatise, so I tend to neglect preaching on the epistles.
My childhood church used offering envelopes with six checkboxes on them, a sort of spiritual scorecard. When I finally met James, hiding behind Paul, I proudly showed him my envelope. He laughed.