Had a surprisingly good experience on a short flight out of CMH the other day. Didn't get upgraded but after departure the First class FA came over to me in economy, thanked me for my business and asked if I needed anything (they were only doing water service in economy). She grabbed a white wine for me and was consistently checking on me while working the First class cabin throughout the flight. Ended up giving her one of those GS compliment cards at the end of the flight and she seemed ecstatic. I still have no idea if they do anything...
Anyway, at least on flights with few GS, this is what I would always hope for service wise but rarely get. Seems to take little incremental effort on behalf of the FA's but makes a huge memorable impression. Challenging to ensure consistency when most of the workforce doesn't feel like going above and beyond but what an impact the front line folks could make on GS if they all did this.