I'm not a full-blown hater, but I have problems with that as well. Specifically, you have no control about it whatsoever, you're just promised that "if you do things right, it'll be amazing". And it is! The problem is that any tiny minuscule mistake causes catastrophic failure of performance due to allocations. Since the good performance depends on type stability, and type stability propagates, any mistake anywhere will propagate everywhere. Think: if a variable becomes type unstable due to a programmer mistake, any function that consumes it generally might become type unstable as well, and any function that consumes the output of that function as well, etc. The upshot is that this forces you to think more carefully about your types and data structures. Programming in Julia extensively has made me a better programmer. I'm not a C++ expert, but I believe that in C++ these kind of mistakes always end up being localized.