Keep a good head and always carry a light bulb.

ursulav points to a message from Ursula K. LeGuin, which starts:

I made a note to myself a while ago: "Whenever they tell me children want this sort of book and children need this sort of writing, I am going to smile politely and shut my earlids. I am a writer, not a caterer. There are plenty of caterers. But what children most want and need is what we and they don't know they want and don't think they need, and only writers can offer it to them."

which I think is wonderful.
( On messages )

The bit about messages, I suppose, is one of those things that has to be said from time to time, because no matter how often you say it, there will still be people who persist in not getting it. But LeGuin's opening point, that her job is not to give me what I want, but to give me what I don't know I want, yes, that's what I read for. And although it's a sadness to me that her later books don't achieve it, and indeed sometimes seem to have precisely the sort of message she repudiates, she has done it twice, if not three times, and I owe her an immense debt for it.