In my opinion, the section on data ownership contained the most egregious and unforgivable example of go's flaws. The behavior of append in that example is the kind of bug-causing or esoteric behavior that should never make it into any programming language. As a regular writer of go code, I understand why this particular quirk of the language exists, but I hope I never truly "grasp" it to the extent that I forgive it.
I'm surprised people in these comments aren't focusing more on the append example.