Floating down to Camelot

At least with adults, they've already made up their mind about whether they like reading or not. They can try books in a list like this, realise they don't like an individual one, and move on. It's more dangerous with children because they're just beginning to form their attitudes and can be put off for life by one bad experience - especially if coupled with a well-meaning parent or teacher forcing them to keep reading it to the end, thinking this is for the best.