What I dislike worst is the denial of the Go community and creators, claiming that generics are too complex and that you don't really need them.
I dismissed Go not because of its lack of abstraction power, but because its authors and community is incapable of admitting problems when they see them. A similar problem with CoffeeScript (conflation of declaration and assignment + scope rules) and the authors' refusal to admit that there is a problem also made me dismiss it entirely.
Every language/platform has problems. But not every language is in denial of them. We should all avoid those that refuse to acknowledge their problems - because that points to a much deeper, much more serious problem - a problem that cannot be eradicated with technical means.