I think people need to understand core concepts of the field, but honestly, you will do fine in most jobs if you don't use certain concepts, ever. Say, decorat

I think people need to understand core concepts of the field, but honestly, you will do fine in most jobs if you don't use certain concepts, ever. Say, decorators. Or metaclasses. Lots of those are hairy little edge features of a language (where some are quite useful features you should be teaching to new people in your shop if they don't know them already).