[berkut]

Memory management is extremely important for high-performance code. And C/C++ allow you complete control over it, but obviously with extra work needed to do this. But when you need the speed, it's so worth it, it's not funny.

On top of this, things like bit-packing and tagged-pointer type things can allow you to save memory, allowing you to fit more stuff into cachelines more efficiently, giving even more speedups.