Reading about this stuff reminds me of watching a grass fire: there's a huge amount of smoke and activity going on, but I'm really not sure where the flames are

Reading about this stuff reminds me of watching a grass fire: there's a huge amount of smoke and activity going on, but I'm really not sure where the flames are -- or if it should concern me. Working with Ocaml and F# over the past few years, in small and smallish medium-sized systems, I've been fortunate to have an environment where I can use any paradigm I want in a natural setting. And while I've gone from an OO-diehard to an FP fan during that time, I haven't given up on objects. I think systems "mature into" objects. I do not believe they should start with them. (Which is completely opposite of what I thought several years ago) Functionality gets created, tested in various scenarios, and then -- and only after a good amount of exercising by various other systems -- does it get grouped into ADTs, objects, or whatnot. Note that I am describing how these things are created, not what they are. For practical purposes I could care less whether this chunk of bytes is exposing a service or providing a type. Of much more immediate concern is why should it be in this shape? I think if you start functionally, you are free to let the problem domain determine the shape of the mature code. Whereas if you start with some kind of preconceived notions of where you're ending up and why, you're making assumptions about the optimized solution that may have no justification. tl;dr -- you're asking the wrong question.