I had a really nice experience recently. I was boarding a flight from PHL-IAH. I had received an upgrade. After I had taken my seat, the gate agent came on board. He shook my hand and gave me a personalized Thank You card for my 20 year anniversary as a frequent flyer with the airline. He said he was a Global Services agent. He then asked the flight attendants to "take good care of him during the flight." This was really special to me and goes a long way to make up for the occasional glitch during travel.