For me, I am more likely to be unfriendly to a passenger rather than an employee anywhere in the airport. I might actually need something from those employees! If a passenger is being an idiot in a way which affects me, I don't take too kindly to it.

There's no reason not to be friendly and say "thank you" to the front-line AC staff, it's been a very trying time for them. I have my first flight with AC in almost 4 months coming up... looking forward to seeing some of the familiar faces in YVR/YYC again.