Caterpillar

Spreadsheet software is great! (I'm using LibreOffice Calc quite regularly.) The way it combines data model and user interface is awesome. It allows you to get started with some quick-and-dirty calculations quite easily, and gives you as much insight as you need, into what is happening.

But for any spreadsheet that grows beyond trivial, it also sucks. Those cell IDs don't compare to good variable names. Copy-pasting cells is a poor excuse for code reuse. For these reasons, refactoring gets quite messy. And when I need to do some real programming, I need to dust off this weird BASIC that I can never remember how to use. (Or I'm doing it wrong. Also quite possible!)

Maybe an interactive programming language with good tooling can fill a similar niche, but in a cleaner and more powerful way. You write code from the start. You have insight, because you see what every single expression is doing. If you combine that with a really simple UI library (like, not much more complicated than the cells of a spreadsheet), maybe that could really go somewhere.