[zzzcpan]

> You spread your (probably stateful, imperative) logic over several files and classes.

It's just as awful in Go code that uses interfaces. State changes are still scattered all over the place. You still have to keep a model of everything in your mind to understand what some method does and what states it changes and what effects those changes have on other methods and so on. My point is: interfaces don't offer noticeable improvements over inheritance.

Building abstractions around state changes instead would be much better way, especially considering that Go supports function literals and closures. But nobody does that :( People prefer to abuse interfaces.