[cgh]

Lifetimes qualify as esoteric, I think. They seem unique to Rust (please correct me if wrong) and are not immediately intuitive.

[duped]

C++ developers deal with lifetimes all the time (grep for "outlive" in a large codebase, for example). It just isn't baked into the language.

The notion of the "lifetime" is fundamental to systems programming, particularly when dealing with concurrency. It's quite natural to folks who are used to dealing with use-after-free/use-after-move and iterator invalidation bugs, imo.