DBA's are from Mars; Developers are from Venus
They say that DBA's are those who put people into two categories: People who put others into two categories, and people who don't. Perhaps we're not quite THAT bad, but we do tend to see order in our world.
But we see it in a particular way. I was reading a blog recently from my friend Ed Wilson (Microsoft's "Scripting Guy") and he talked about a book he read on taxonomies. It seems that many developers are looking for that perfect hierarchical structure - and as a DBA, I don't believe in those. I think all data is really meta-data, and it seems to me that any element is the sum of its descriptors, and after that it is only relationships. Sure, you can make an element and a set of relationships into a hiearchy, but why limit the data that way? Why not just think of elements and relationships, and then make those relationships do whatever you like?
Break the chains of hiearchical lists, my developer friends. Break those chains!