Art is supposed to be challenging; what is design supposed to be?

According to jazz musician Henry Threadgill, art should be challenging. From an NPR interview:

Threadgill says art is supposed to be challenging, and that he doesn’t care if his audience likes his music, as long as it moves them.

“My only hope is they’ll have a reaction, and the reaction doesn’t have to be positive,” Threadgill says. “It could be negative. It’s fine with me if I drive you away. That’s as good as if I kept you there. If it was strong enough to run you away, then it’s going to do something to you. It’s going to make you think about something. It’s going to make you feel something that you weren’t feeling or thinking about before. And that’s the whole idea.”

Generally speaking, I agree with Threadgill, although this doesn’t always have to be the case. What’s challenging to a person is a somewhat subjective idea anyway. Most American’s ideas about art, I’d venture a guess, make them think about anything fluffy and sugar-coated, warm and fuzzy. Most Americans, thus, aren’t going to be interested in war-related images to hang on their walls and set on their shelves. They’ll be thinking of pastoral Kinkade’s or wildlife or an innocuous architectural scene with impressionist brush strokes — pictures in their head that sooth, not challenge.

Going with the idea that art should be challenging, though, I’m wondering what design should thus be. Should design (architectural and interior) actually be geared towards giving us a sense of comfort while the art within our spaces pushes our boundaries, asks us to think outside the box?