I was upgraded in Dec. from economy to buz. on the first flight as AA Executive Platinum. It was NRT-HKG and I just thought it was overbooked. (I did not check the back cabin.) For this flight, I even requested a special meal, Asian vegetarian, just because I think it's better than regular foods in economy.
I thought my meal request was simply ignored and it was OK for me. But to my surprise, a cabine attendant came to me and told me that they can meet my special meal request. Then I told them I'd rather want to have Japanese meal in buz, which I like a lot on CX. And she went back to the galley and came back and said they can accommodate that request, too!
Before touching down in HKG, I was also given a box of chocolate (the one they usually pass out chocolate from after the meal in buz.) and said, 'Merry Christmas.' As it seems I was the only one given this, I really wondered why they treated me that good. It was a nice experience, though.