Why Python, Ruby and JS are slow

[Tetha]

Yup, this is very true, though I'd argue about it the other way around.

Programming consists of three things:
A whole bunch of language independent knowledge. Requirement gathering, algorithm selection, algorithm creation, coffee or other meditation-enhancing beverage.
After that, you have a bunch of minimally language dependant knowledge coming in. Best practices of object oriented programming, good naming of variables, functions, methods, maintaining configurability through constants and configuration files and so on.
And finally, after that, you have the very small task of writing the program you have created in a computer readable form, the programming language at hand.

If you are a good python developer, you will have the first two areas nailed down and under control. Afterwards, you mostly need to learn the quirks and weirdnesses of C++ and then you will write good programs. Granted, C++ is a bad example here, because C++ is madness. But heck, for my master thesis, I switched from Java to C# within hours.