Speaking from personal experience, I'm usually pretty good about waiting, offering a polite nod, etc. If I'm not, it's probably because I'm on my fifth flight of the day or couldn't sleep the night before and I'm extra crispy at the time. I
will say that the
#1 thing I like is when the agent recommends a time for me heading to my gate, as happened at JFK this week: They let me know my flight was delayed (I thanked them, noting that I was coming upstairs from the delay...late pilot) and suggested the time for me to head down for the rescheduled departure.
This isn't as big of a deal at, say, JFK T2. However, at JFK T4 (or
anywhere in Atlanta) this is a
very deeply useful and appreciated touch, right alongside quickly getting a ticket reprint when you've just been IRROPSed.