Interface

I’m still in the process of learning golang the right way. Yes I already wrote some projects with the Go language (here and here), but I like to understand the real meaning of techniques when using them.
One of what is said to be the most amazing features of Go is interfaces. Here’s what the official golang docs has to say about it:

Interfaces in Go provide a way to specify the behavior of an object: if something can do this, then it can be used here. We’ve seen a couple of simple examples already; custom printers can be implemented by a String method while Fprintf can generate output to anything with a Write method. Interfaces with only one or two methods are common in Go code, and are usually given a name derived from the method, such as io.Writer for something that implements Write.