JAL always have the most courteous and apologetic cabin attendants in my experience.

One time, I wanted to do the paid upgrade ($350) from Economy to PE at check-in. The check-in attendant told me that due to an equipment swap (787 v2 -> 787 v1), there wouldn't be a PE at all on my aircraft. I was a little disappointed, but I thanked her and went on my way.

Once we were boarding the plane, it became clear that the plane being used was the 787 with PE, after all. I asked the cabin attendant at the door if it was too late to go back out to the gate and upgrade. She went to check for me. When she came back, she apologized and said they weren't able to process any more upgrades for the flight, paid or otherwise. I thanked her again for the trouble.

She walked with me all the way back to Economy and then pulled me into the galley. She said, "I see you're at the back of Economy. Sometimes people there don't get all the meal choices because we run out. Let me know your choice and I'll put one aside for you." Again, I thanked her profusely and said that was very nice of her.

Once at my seat, the head cabin attendant came over prior to take off to introduce herself and apologized again that they weren't able to accommodate my upgrade request.

And finally, during the first drink service, yet another cabin attendant apologized again about not being able to work out the upgrade, told me she was servicing my section of the plane, and told me to let her know if there was anything she could do for me.

To me, that's going above and beyond in terms of service. I actually felt sort of bad because I didn't mean for everyone to make a big deal out of it. Although I'm a JMB Sapphire now, I wasn't anything at the time, so it was nice to see them do all that for basically a "nobody".