This was exactly my experience when I was working in Go. Each line was easy to understand, but reading actual code was painful because I needed to read so much to figure out what was actually being done. I was basically spending 90% of the time mentally simplifying the code into abstractions so that I could understand the business logic. Then once I understood the business logic I had to zoom back in to check that their inlined reimplementation of various basic data manipulation routines were correct.