My wife grew up speaking Polish and hadn't encountered many of the children's books I grew up with, and I can definitely attest that she's found some of the classic children's novels I shared with her very strange -- she couldn't get her head around Alice in Wonderland at all, and I realise it barely holds together as a story when you read it as an adult -- but I remembered it so fondly from childhood. I'm always surprised when people say they noticed the Christian allegory in the Narnia books as children -- I was brought up as an atheist, but I went to a Catholic school, and I still managed not to notice Christianity at all in the Narnia books until Lucy references Christ directly at the end of Voyage of the Dawn Treader. I still think it's a fairly subtle metaphor, but a lot of other people say they felt like they've been hit over the head with it, so maybe I'm just slow on the uptake.

In general, my wife has consistently preferred realistic children's stories over fantasy ones, even though she's a big fan of adult fantasy. I think children's fantasy (or some of it) doesn't try as hard to make sense of its fantasy worlds, and that may be a stumbling block when we encounter it as adults.