> So, for those of you who are willing to explore the part of this that goes beyond a simple rational analysis and criticism of language design, whats bugging you?

Error handling is a big one for me. This could be generalized to lack of expressivity; it takes an unreasonably large amount of code to accomplish anything. Generics will help with the general case, but they don't do anything for error handling.

Lack of sum types, as you already mention, are another.

Go really likes forcing you to either write a ton of tests or discover your errors in production. More expressive features (sum types, etc) effectively mean that compiler provides those tests to me for free. _Can_ I write them myself? Yes, obviously, but that brings us right back to having to write way too much code to accomplish anything.

Farther down the list is escape analysis. Rather than just giving me control over whether allocation happens inline or indirect, if I have some performance critical submodule, I have to sit there and box with escape analysis; this is not only time consuming, but extremely brittle.

https://fasterthanli.me/articles/i-want-off-mr-golangs-wild-... is a good read for fairly specific issues that _mostly_ haven't directly impacted me, but on the rare occasion they have, they've been infuriating.