Read Roger has a conversation going on (Crap, here comes the Teacher!) that talks about didacticism. Right now there are over 50 comments.
My two cents worth:
Do I like didacticism or message books? Hell no.
But doesn't every book have a message? Is it not so much about the message as how it's delivered? Hell yes.
I look at it this way, whether it's a book, a TV show, or a movie.
Yes, I know there is an author / writer/ creator. But the minute Oz shows himself behind the curtain; the minute I know that my strings are being pulled by a puppet master; I'm turned off. For me, the moment that the message overwhelms the story you've lost me as a reader, and this usually happens when the author lets the message get in the way.
In addition to that, if the message is so heavy handed that it's like getting hit on the head by an anvil, you've lost me. I'm not stupid. Get too heavy handed (this is important! you must take this message away with you!) and you've lost me, because I don't like to get beat up.
Let me add: this is true whether or not I agree with the message; tho to be honest, I'm probably more forgiving and willing to ignore it if it's a message I agree with.
How can I tell when this happens? Characters act unlike themselves; speeches are given that take away from the whole; events happen that don't make sense; consequences are over the top. In other words, the story is affected and manipulated in order to have the message delivered. It's one of the reasons I didn't like This Is All; I felt as if all those things were happening in order to deliver a message, and as such the characters and events never stayed "real" to me.
Edited to add: One more thing about the Read Roger comments: there are way too many people using anonymous. OK, for whatever reason, you don't want to use your real name but for the love of Mike, pick a pseudonym and stick with it. Trying to keep track of who was who is way too confusing, gives less weight to their argument, and makes it difficult to follow the conversation and the points being made.
Thanks to Monica for letting me know about this conversation.