I've been a PM for several years and just made it to DM a couple of weeks ago. I'm generally not much to complain, but in the past when I was dissatisfied I would send an email through delta.com and generally got a fairly canned response via email.

Well last week, I had a really bad experience with my family returning from vacation. So I fired off a note simply expressing my dissatisfaction with the whole arrival experience at JFK. I was expecting a simple note back, but I actually received a phone call from a customer service rep in Atlanta followed by a personal letter from Delta's manager of JFK apologizing for the mishap. It doesn't undo the experience that I had, but I was fairly impressed with the attention that Delta gave to the follow-up.