Have you heard of The Gratitude Campaign? Scott Truitt, founder of the campaign began to say "thank you" to Service Men and Women he saw on his travels. There were times he was not able to speak directly to the military personnel so he looked for an alternative. Scott says, "I did some research and found this sign, originating in 18th century France which, fully translated, means "thank you from the bottom of my heart.""
Put your hand on your heart and lower it down toward the person you are gesturing to. They will know how you feel.
Gratitude can be a way of life.