As the child of two art school dropouts(*) this is a topic which both fascinates and irritates me. I wrote a bit about it in More thoughts about Art and responsibility
collects some recent discussion in writing, ART, responsibilities, powers, contexts
which capture a lot of my annoyance. (She also has a lot of interesting things to say for herself, but they're less relevant to my rant)
I guess I see "challenging" yourself and other people, and art, as two separate things. Not orthogonal, but not all art challenges and not all challenges are art(**). I also get Really Annoyed at people who claim that the quality of a piece of art is directly proportional to the strength of the response it creates, since then they rely on cheap easy gimmicks to get strong responses (Religion+violence+children+excrement, say)
And if the point of your art is
to be challenging: what are you challenging? Does it actually need
challenging, or are you again taking cheap potshots? See, for example, all the "edgy" comics who poke at political correctness but not at the genuinely unquestioned aspects of their society, since audiences would much rather laugh at the oppressed than themselves.
Not that there's necessarily anything wrong with taking the easy way, but if you do you can't get all high-and-mighty about how Important and Unique your work is.
(*)Who, afaict, feel much the same way I do. And between them they do actually have all the courses for two fine art majors, but being
Stereotypical Arty Types they just never got it together enough to graduate :)
(**)And any artist who justifies their art by saying it's challenging, then freaks out if anyone challenges them
about the assumptions and subtext of their work is a hypocrite. EDIT: I mean freaking out at the idea
of being challenged, obviously you can object to any given challenge if you think it's wrong.