Everyone take notes: even one really nice gesture like this will get you YEARS of great service.
I take care of everyone who provides me services at Christmas, and in return they go above and beyond for me. Those people include:
-the garbage men
-the mailman
-my hairdresser
-my massage therapist
You would also be wise to take care of the staff at your doctor's office, and your kids' pediatrician's staff too. It's amazing how they can magically find an opening right away for someone who has a goody basket (sweets, cheeses, fruits, ect) delivered close to the holidays, but the doctor is 'fully booked' when most patients call hoping to get in right away.
The hardcore socialists among you will bristle at these suggestions, but in the real world greasing people's palms with cash or presents will get you better service 99 percent of the time.