I'll try to summarize as I could write many more paragraphs...
Promoted to manager/lead of a new team that would split off from the existing test engineering team - this new team will be responsible for all test engineering work for our system products, which I'm an expert in. Been doing development, design, and characterization work on them within the R&D group for the past eight years. I was promoted based on the talent I showed in fixing the absolute mess of test programs we had for our system products, since the test team was nowhere near capable of handling it themselves.
I'm experiencing idiotic resistance from the current lead of the test engineering team in every single new perspective or idea I bring to the table on how we can improve the efficiency and ease of test development. Won't even discuss them; you'd expect some back and forth to refine the idea, but no - nothing. Everything is "impossible" and simply can't be done. This guy's work is sloppy with zero documentation and he's one of those people who only does the work for the present and gives no consideration to any long-term effects. Everything needs to be done his way even if it's wrong. Not very many people are thrilled with him, even those working for him.
Basically told by our boss that while I'm the expert in our systems, she has to defer to him on test development since he has a couple of years of experience in the new test system over me (I've worked there for ~11 years, while he's been there for ~9-10 years - I took the R&D route while he took the test engineering route, and he was given a management position a couple of years ago due to departures). I get it, she needs to stay neutral. But two years of doing it wrong means nothing to me. I also figured that I was promoted because I proved I was able to competently do test development on my own, not because they just liked me that much. Even told by the President that the current test team "doesn't know what the fuck they're doing."
I'm seriously considering either going back to the R&D department or finding a new job. Either wouldn't be difficult for me at all, but I know both options would put the test team in a horrible position and be awful for the company. Another option is to just stay where I am, let him do it his way, and be there to pick up the pieces (again) when everything fails.