Traditionally, a luncheon is a lunch that takes an eon. - Judith Martin

Dear Miss Manners: What is the proper way to eat potato chips?
Gentle Reader: With a knife and fork. A fruit knife and an oyster fork, to be specific. Good heavens, what is the world coming to? Miss Manners does not mind explaining the finer points of gracious living, but she feels that anyone without the sense to pick up a potato chip and stuff it in their face should probably not be running around loose on the streets.

Miss Manners has always believed that people who do not acknowledge presents are annoyed at receiving them, and she respects that preference.

The polite thing would be to say to the noisy person, “I beg your pardon, but I can’t hear the music. I wonder if you would mind talking more softly?” By the time you have said all this, a third party will utter a loud shush, thereby accomplishing your purpose without sacrificing your manners.