I personnaly find the ownership thing really hard to get. That's the thing that protexts you from screwing memory in parallel code but the thing is you have to use it even in non parallel code. The other thing is that it's a set of rule which mixes with the type system, so at the beginning, I had hard times understanding if I had issues with my types or with the ownership (eventhough, I know, ownership issues are reported as such by the compiler). So in the end, you have to think about memory safety much more deeply. I get that my code really feels right once it's written with ownership principles but somehow, it makes Rust hard to start with. Now, this ownership part is something really new to me (I have ASM,C++,Python,Java real life experience), it makes me think better about about my programs. So it's a tough but fruitful experience.