Late night train, almost deserted. Handful of people in the quiet carriage. Silence apart from two people who are chatting at the top of their voices, especially the young woman of the couple, who has regaled the carriage with how drunk she is right now, her 17st friend, what she's studying at Uni, her future career plans - all punctuated by the most asinine and penetrating laugh I have ever heard.
WIBU to go over and tell them to be quiet or else move their v loud conversation to a non-quiet carriage?
Mumsnet jury - you decide.