Named parameters. Even the first one. I don't know why named parameters aren't a thing outside Apple languages. They save so much time referring to documentation and jumping around between different files and code.
I know two: Ruby has keyword parameters. Elixir kinda has keyword parameters.
Typing. No unchecked exceptions. Optional memory management. (I think D has all of this)
Operators that aren't overloaded and all syntax tokens only comprised of 1 character.