I feel like C++ is not just big, but in arcane ways. Like needing to know move semantics, but for being such an important concept, there's very little in the way of the language helping you understand it.

Also, it's changed a lot. I learned C++ as my first language, but haven't used it nor kept up with it for the past 15 years. I'm pretty sure that idiomatic C++ is just a different language now than the one I learned, despite the name and basic syntax staying the same.