Concurrency is one of the most complex problems we (developers) can face in our daily work. Additionally, it is also one of the most common problems that we may face while solving our day-to-day issues. The combination of both these factors is what truly makes concurrency and multithreading the most dangerous issues software engineers may encounter.
What is more, solving concurrency problems with low-level abstractions can be quite a cognitive challenge and lead to complex, nondeterministic errors. That is why most languages introduce higher-level abstractions that allow us to solve concurrency-related problems with relative ease and not spend time tweaking low-level switches.