The morbidity of children never ceases to amaze me. Death, in play at least, doesn't seem to frighten them. I guess its the same among adults, but it's interesting that make-believe and reality are seperable even at a young age. I don't think we adults give kids enough credit for how sophisticated they can be. (Probably because there are a lot of areas where they aren't and it's easier to just bucket them in whole.)
One thing I (thankfully) realized pretty early on when raising my kids is that they're fully-intelligent humans pretty much from the start. They just dont _know_ stuff, but their intelligence is all there from a much younger age than most people seems to think.