The root of gratitude is recognizing the specialness of a situation.
You are grateful for things and experiences because you feel they are rare.
Understanding that everything is unique gives us many more opportunities to be grateful.
The odds of a deck of cards being shuffled the same way twice are so low that there is virtually no chance no matter how long the universe exists that two decks will be shuffled the same. This perspective allows us to be grateful to be the person who plays with a shuffled deck.
The chance of two people having the same DNA is virtually zero so be grateful for just being you.
Look at everything in your life as if they were special, as once in a universe. The specialness of them gives you the perspective to being truly grateful