Black Walnut, I agree with Joe that they tend not to take themselves too seriously. They do take the music seriously but not themselves. Costumes, when used, are just part of the country music tradidion; remember, it's supposed to be a sub-category of commercial country music. The folk roots may be clearer and stronger but a bluegrass show is supposed to look like it was staged, not like a university lecture.
Over the years I've found that there are may things in the world that can be more easily appreciated if I let go of my own notions about what they should be and just accept them as I find them. Most of the fine arts and liberal arts seem to be like that. Come to think of it, people are mostly that way too.