[dagoat]

> Every possible best pattern and practice (including the ones that were still a few years away) I'd already done them and perfected them.

Care to provide examples of the patterns? Genuinely curious

> I was so high up on the peak of the C# mountain that recruiters could no longer understand me, employers could no longer understand me, co-workers could no longer understand me

What sort of things were you saying that led to people not understanding you? I can't imagine knowing a language so well that others can no longer understand me

[Jach]

Not the OP but I can maybe guess at some of the examples. In Java (and I assume C#) because you don't have a powerful enough object system, you end up having to write contorted code often making extensive use of various "design patterns" in order to support testability, the SOLID principles, not having to rewrite a bunch of existing code, and so on. So much of that melts away when you instead write in a FP style, or use a more powerful OO system (like CLOS) or use a dynamic language. I've worked with people who couldn't describe the most commonly used patterns in Java (Visitor for instance) or techniques (e.g. "Dependency Injection") but also people who seem to think everything should be expressed with them, including those that are obsoleted by modern Java features.