I agree that micro-optimization obsession is a problem in the C++ community, but sometimes it is useful and then it&#x27;s nice to have the option.<p>Personally, I have my own custom hashmap which provides a 10%-15% performance improvement over the std one for my use case, and I also have custom mutex&#x2F;thread code similar to the one listed in this library because it provides better performance when no other thread has the lock, and avoids needing to compile&#x2F;link against the boost equivalent which adds seconds of compile time to any file that includes it.<p>These are all optimisations that I have tested and profiled though.