The MTR (metro) seems to be Hong Kong couples’ favorite arguing place.
I have seen countless couples of all ages sulking, banging on walls and screaming in the stations and carriages. They seem oblivious to the people around them, intently watching, listening and in some cases filming.
More often than not, the argument is extremely loud and the general public gets a glimpse of the couples’ private life.
Nobody interferes unless it really gets out of control. In that case, someone will call the MTR security staff.