Went for breakfast recently and was sat with a friend and there was a table of three next to us. The lady next to us started playing music loudly on her phone who was sat directly behind me.
I asked her “please can you turn the music down” to which she agreed. 5 minutes later someone from their party said to me, “we are in a public place we can do what we want” (they had obviously been discussing my comment 🤣) to which I said it was a polite request. Went back and forth for another minute or so then everyone went back to doing their thing.