bonoboTP parent
For some strange reason Excel really managed to do it. Many many people who don't think of themselves anywhere near being a programmer, somehow get at ease in front of Excel enough that they often inadvertently and kind of unawarely end up learning programming concepts and creating much more complex computational applications than its been possible with any other tool for non-developers.
I have a theory on that, based on something I do that over the years I've learned a lot of my co-workers don't do: When I'm reading code, I have the contents of the variables all in mind and am manipulating them as I read the code. When describing it a couple of times they've said "oh, like a human compiler"... So I really don't know what's going on in their heads, but this seems like the reason I can understand code I haven't seen before faster than most of them.
Spreadsheets flip the usual interface from code-first to data-first, so the program is directly presenting the user with a version of what I'm doing in my head. It allows them to go step-by-step building up the code while focusing on what they want to do (transform data) instead of having to do it in their head while focusing on the how (the code).