Basically, managing memory is hard, and usually the way you manage the memory depends and interact in the way the OS manage the memory (so not your error but OS

Basically, managing memory is hard, and usually the way you manage the memory depends and interact in the way the OS manage the memory (so not your error but OS or drivers...). Also, sometimes your design make it difficult to keep track of your memory because you share pointers to different processes and classes and you usually make this interactions to be efficient and fast. Basically, if you are a beginner, building easy things in C/C++, you can stick to the basic rules so you never fall in this kind of traps, but if you are an expert focusing in optimization (or time sensible applications) sometimes you make assumptions or rulesets so "you can't use this class like this", "you can't never pass a pointer with less than 64 bytes allocated", and after a couple of months and some people and hat changing they end up making mistakes...