First three are clearly documented in language reference, which could be read in several hours (at least before generics were introduced).
* "how is my Cobra command being registered when I'm not calling any code?" -> "oh, there's an init function that registers the command when imported"
* "why is this variable not working?" -> "oh, it's that for loop thing again"
* "why does the result of my unit tests depend on the order of test execution?" -> "oh, we have 150 Cobra commands in one package with variables shared between _all_ of those commands"
* "how is this variable being set?" -> "oh, we have to call go build with a monstrous ldflags argument
* "why is CI not passing for this oneliner when this looked fine locally?" -> "oh, it's a linux-only file so the IDE isn't even showing me simple syntax errors"