[taway32r41]

Like with most languages, learning the language is easy. Learning all the libraries, especially the undocumented proprietary ones, is the hard part.

[zoomablemind]

I'd add that with legacy codebase the hardest thing is to untangle the business logic buried in. Some of it is likely still the core of the business but not many people, if at all, clearly know it and the docs are often dated and no longer in sync with the code.

In one word - minefield!