Do people actually use `interface{}` so liberally? I've never encountered it in the wild (except by newbies or as an example of what not to do) and I've always been under the impression that it's been heavily discouraged for a very long time.
interface{} is heavily used in many of the Go std libraries. Particularly for what I call "convenience methods" where you want to be able to pass in various types and it will do a type switch for you and then determine what to do.
Part of what I was discovering in this blog post is that if you look under the hood at these convenience methods, and you know in advance what type are passing (i.e., you are not using interface{}), you can often find the "direct" call to use that uses a concrete type and likely get better performance out of it.
