> I don't know that you have to hand full control over to the programmer, but if you're randomly flinging values on the heap everywhere (a.k.a. "hash tables"),

> I don't know that you have to hand full control over to the programmer, but if you're randomly flinging values on the heap everywhere (a.k.a. "hash tables"), you're gonna hit a wall long before you get to "C performance". Rule of Python: Everything is at least two pointers away. -- > and CPython is hopping through all these hoops for every such lookup. Actually CPython has a cache for that. This becomes apparent if you improperly replace methods in the class dictionary. I think the bane of Python specifically is a bit different. It's not so much that it's very dynamic, because JITs can clearly deal with that. It's that CPython exposes all kinds of interpreter state that's off-limits in other languages, which makes it way harder to JIT. In JavaScript there are at most a handful ways how you can mutate a prototype, but in CPython you don't have enough fingers to count them, even if you only consider Python and not the C API.