One of the core tenets of C++ is "trust the programmer". One of the core tenets of Rust is "the programmer is a complete numpty; don't trust them unless they sign a contract in blood, in triplicate, promising they know what they're doing."
People make mistakes; Rust asks if you're sure you want to walk into the minefield, C++ enthusiastically runs ahead and blows all its limbs off while screaming "I don't know why you asked me to do this, but anything to make you happy!"
Quxxy on reddit in response to «is most of rust's features only due to a good compiler?»