Names are a requirement, but are actually optional.

Many Flight Attendants do not wear their name tags for the fear of a Passenger getting their name and stalking them. (has been done many times. following to the hotel, searching for their home phone numbers and calling, home address, etc)

Some Flight Attendants do not wear their name tags for the sake of just upsetting the passenger when the passenger requests a name for either writing up cause of bad service or good service.

Flight Attendants are not required to provide a name to the passenger when requested. (same goes for agents)

All you need to write a report is the Flight Number(gate), Date, Departure/Arrival cities, seat you were sitting(how may agents there were).

When you write a report on one Flight Attendant, all Flight Attendants on that particular flight get written up. When you send the report to Headquarters, all they see are the working crew members, and thus, send the entire report to the base, and have the base supervisors discipline.

When you are on a wide-body aircraft, that is why it is good to have the Purser involved cause the Purser always writes a report, and can specifically detail who/what happened.