^^ Listen to this! As a manager and developer as well, I 100% agree. If you are a great worker and your manager isn't incompetent, they will fight for you up the chain. But don't approach it abrasively at first. That just sets the wrong tone for everyone.

On the other hand, if a good manager doesn't care if you quit, it also says a lot. There are developers I was so relieved just quit. It wasn't worth it keeping them.