> or if you happen to have a notion of OO in Go that is hard to let go of?

So much this. I think Go's interfaces are widely misunderstood. Often times when they're complained about, it boils down to "<old OO language> did interface this way. Why Go won't abide?" There's insistence in turning them into cherished pets. Vastly more treasured than they ought to be in Go, a meaningless thin paper wrapper that says "I require these behaviors".