FMIL is trying to figure out with FI what song to choose for the mother/son dance. Initially, she said she was only coming up with songs that would be better for FI and I (dare I read into that?) but did end up giving a couple suggestions. Then she asked if we had picked a song. FI, thinking there would be no issue in telling her and making her feel included, said, "we're going with X" and then expressed opinions on her mother/son suggestions. She wrote back with more suggestions for what our first dance could be, which honestly are terrible and much shallower in feeling.
Why is this a discussion into which you feel you can insert yourself?? It's our first dance. We said we picked it. Enjoy that you have advance knowledge of what it is and don't try to "improve" upon it and make it more your style. Back the fuck off.
Beyond that, the songs that she's suggesting for the two of them have a distinct "I owe everything to you" vibe. But that's unrelated.
What things are people suggesting which you consider totally inappropriate?