That's important: don't be afraid to look into the stdlib source code when questions arise. It's easy to read and stuff is easy to find, and it's also a great teacher.
Since go, this has been a really great way for me to judge a langage: how readable is the stdlib ?
If it's layer upon layer of unscrutable abstractions, then you know there's a high chance your codebase will end up looking the same after a few years.