There is a different between muttering a reflexive "thanks" and really focusing on making a connection with whomever you want to know you appreciate. Part of my life 'shake down' helped me truly remember my Mother's teaching by example that we are all human beings and deserving of being seen as such. I have also found that this is one area where the concept of Karma can be seen in action.
Try this experiment: Tomorrow when you get your morning coffee from the barrista look at him/her.
See the PERSON not the job and share a smile and THANK YOU.
Even if the service sucks and your coffee takes an extra 20 seconds, do it.
Actually do it ESPECIALLY if the service sucks and your coffee is slow in coming.
Imagine that the young woman who is foaming your latte has just learned her beloved pet has terminal cancer, but came to work anyway because she has to pay her rent and the vet bills.
Imagine the middle aged man (who you suspect is the owner of the franchise but who still makes the coffee) is stressed because two of his employees have strep throat.
Give the person MOST in need, a smile and a sincere nod of gratitude.
You will improve that person's day . . . and I guarantee, you will improve your day as well.