Much larger projects. More and more often you are working on just one aspect of something bigger, without having a good grasp of the whole thing. Situations whe

Much larger projects. More and more often you are working on just one aspect of something bigger, without having a good grasp of the whole thing. Situations where you and maybe a small team own entirety of a project are less and less common. Concurrency and multi-threading. To get good performance you used to care about a single thread on a single CPU core that you had exclusive access to. Now you have to utilize multiple cores, care about context switches and in even more extreme cases handle NUMA memory architecture. It's hard and the fact it's slightly less hard with go is one of the reasons of the language popularity.