Back to the topic, I hear THE Speedbird regularly and THE Virgin every now and again and the eyes just roll. I'll have to try the previously posted responses for a laugh.
I believe that although we are all performing our jobs in a professional manner, a bit of recognition that a person is at the other end doesn't go astray, workload permitting. If it's quiet, what's the problem? I'll regularly thank a pilot if he's made my job easier or apologize if they've been stuffed around (usually by maestro, but sometimes by me). I know it's not required, but if I go out of my way to facilitate a pilot request, acknowledgement is appreciated... its just like a wave when someone lets you into traffic whilst driving.
As far as the "G'day" thing, I use it almost always and you can usually tell those few who don't like it by their refusal to say it and the tone of voice. I say "contact xxx on xxx.xx, g'day" and the response is "xxx.xx, ABC, g'day" or no G'day as you please, but if I don't say it and it gets said to me, I either have to make another transmission or sound like a rude git. I prefer the friendlier approach.
Cheers,
R-S.