Which concepts do newcomers to Rust struggle with? 

- Lifetimes, especially static and serde deserialzer
- Traits vs classes
- Dynamically sized types
- Object safety
- Sum types

What else?

Rust + decentralized databases. I have one goal in life: the ability to stop thinking at will

Dealing with packaging and entirely awful crates registry

Building TokenOps.xyz - token distribution 

Figuring out what's used, how popular it actually is against it's competitors, finding the competitors in the first place, people barely write documentation because of the supposed self generated crates descriptions