After a flight from Atlanta to Santiago, Chile I wrote the Delta complaint department with complaints that included a ticket agent claiming I had a special seat I requested at the counter and him laughing telling me to enjoy my flight. The laugh was that the joke was on me because he gave me a much worst seat, I guess because I bothered him by asking. The ticket agent had no name tag so I could not comment by name.
The flight service was terrible, I had just got off a Korean Air flight and it was night and day comparing the service.
I took the time to write and give constructive points, however, Delta expects bad comments, it they did not I would have heard from the airlines.
Although I am a American citizen I encourage everyone to fly foreign airlines if they enjoy good service. Korean Air flight crews are great, however, if you have paperwork difficulties their middle management is terrible with customer service. Emirates Air, Singapore and Thai Airlines are all good. Vietnam Airlines I flew for the first time this month and they were a very pleasant surprise.
I still fly Delta and other U.S. airlines when I have to but I realize that the service will be less then taking a Greyhound bus. Customer service is very difficult with the general public and most U.S. carriers have given up trying with Delta leading the way.