I currently see myself as a recovering OO-aholic - does that explain my position? 
Now while real life -aholics need to abstain completely I simply have to come to terms with my disillusionment of what OO can actually accomplish. I don’t throw out the baby with the bathwater. I don’t define OO in terms of what can be accomplished within the confines of Java or C# and I’ve spent enough time with the SOLID principles to get a glimpse of some core insights that may be applicable outside of OO.
But at it’s core OO is an approach that [adds complexity] (http://www.cpptips.com/heuristics2) to manage complexity. Quite often maintaining state inside an object feels like sweeping the dirt under the rug - and justifying it because nobody can see it because “it’s encapsulated”.
But in the end even Effective Java 2e recommends:
Item15: Minimize mutability
Once you make immutability the default (in order to minimize mutability), state becomes a troublesome concept and you have to rethink the way you process information.
Note that the blog is 14 years old - and back then I would have agreed wholeheartedly because from that perspective functional programming simply looks like pumping DTOs through functions which doesn’t seem that far from procedural programming. But procedural programming doesn’t have first class functions and functional composition.
And while it seems easy to compose stateful objects, the resulting artifact of an object network is notoriously difficult to “reason about”. Processing immutable data structures through composed functions tends to be much more predictable.
Michael Feathers: :
OO makes code understandable by encapsulating moving parts. FP makes code understandable by minimizing moving parts.
So when it comes designing collaborating processes I usually prefer (near-)stateless data transformation arrangements rather than approaches that require long-lived stateful (thumb-twiddling) processes. Note that this is merely a preference guideline as state can be useful, especially if it only exists temporarily and when it is used with extreme discretion.
