There was a whole list, but I can only remember these three:
1) Never harm a child
2) Never write a comedy about another race or gender
3) Never kill a pet
Obviously there are movies that have managed to break these "rules", but the general consensus was that if you wanted to actually SELL your script, you should avoid those things like the plague.
I've been thinking about this list a lot as I struggle through my current novel.
You see, I want my villain to do something absolutely horrific...which in turn would be the motivation for another character to do something equally horrific, but if I do that, I fear I'll never sell the book. (It's not an unfounded fear since I ran the idea past my agent and she agreed.)
I want to sell this book AND I want to make it the best story possible. I haven't figured out a way to reconcile those two desires yet.
You'd think I could figure it out. After all, Maggie Lee in CONFESSIONS OF A SLIGHTLY NEUROTIC HITWOMAN gets paid to kill people, but most readers would say I've managed to make her a fairly sympathetic (even likable) character.
Still, I'm stumped at the moment.
What are the kinds of things you'd never read? What makes you put down a book and never pick it up again? What sorts of things make you tell your friends "don't read that book"?