Reading fairytales also means of course reading between the lines. One of the things I love about fairytales is they usually have a fairly strong message behind them. With Hansel and Gretel, I pick up the obvious anti-child cruelty theme but also the importance of sticking together and supporting one another. Had Hansel and Gretel not done this for each other, they wouldn't have survived in the tale, which is the whole point.
The nice thing about fairytales also is the story shows you the message without preaching it. It is by far a more effective way of getting the message across and something we should all aspire to with our own writing. I know I find it far too easy to slip back into "telling" though flash fiction writing, with its tight word count,does help me against that (there's no room for it!).