Some people are just thick and should stick to picture books.
I've been accused of 'using big words' by people in my social circle so should I dumb down my vocabulary just to please them, or should they try to improve their vocabulary to give themselves a wider range of tools with which to communicate?
I don't believe in dumbing down at all - yes, it's the duty of an author to communicate effectively, but not at the cost of his own literacy. If someone doesn't 'get' what he's trying to say, sometimes yes it is the reader's fault. But then - are those the sorts of people you want as readers anyway? There are plenty more people out there who are willing to improve themselves.
Mediocrity, and people who are satisfied with superficiality really rip my nips, especially when it comes to literacy. If someone's that shallow I couldn't give a flying f*** what they think of my writing. Or anyone else's.
I'm with scarlet on this, even if it means Mr. Ferret hates me, too.
Some may say it's the duty of the author to communicate effectively and know his or her audience. Well, yes, kind of: as a writer I write for my own intended audience, but that doesn't mean another reader won't pick up my work and read it. If he doesn't "get" it--well, then I really don't care. He wasn't who I wrote it for. Might he have enjoyed it anyway? I hope so. I try to make my work enjoyable on many levels. But if he just didn't get it while most of those other people I'd intended my writing for did get it, then it's his own fault, and he won't read my next work.
Not always the most marketable move to hope to be a Jonathan Safran Foer or David Foster Wallace over a Dan Brown, but that doesn't matter to me. I don't enjoy Dan Brown anymore. Many of the people who do, wouldn't like DFW. But I would cry if DFW tried to be more "marketable" or "accessible" at the expense of his great writing.