Year round I say please and thank you and ask the FA/Crew how they are doing
And its not just once at the end of the flight, its every time they bring me something or take something away
As far as holiday gifts go... I think its just something nice to do so I do it
I've got a few flights on the day or 2 before x-mass
SYD->SFO crew is getting a big box of lindt chocolates and a box of cadbury favorites
SFO->DEN crew is getting pack of tim tams per FA/Crew
DEN->RDM Crew is getting a Pack of tim tams and a $5 starbucks card each (EX crew need the coffee)
Got flights back to Syd on the 28th, still working out what to do for them