I laughed with joy when I saw this quote several days ago and I'm smiling still. It's funny now, but I used to think that it was not only possible to have too much gratitude, but that I would run out of it, change my thinking or something.
Many years ago (many), I studied TA or Transactional Analysis which was a brilliant way of seeing how our minds work and how to interact better with others as well as ourselves. In that, there was the talk of the warm fuzzies and the cold pricklies. Sometimes people would think that there was a shortage of warm fuzzies, so they would reach in their bag and give out cold pricklies instead so that they didn't run too low. But I never related that to gratitude as I do now. Very interesting.
Since I've become a grateful man, I find myself in gratitude so much of the day in thousands of ways with thousands of shades of feeling. It is amazing how a beautiful sky at certain times of the day can almost bring me to tears in how grateful I am to now actually see it when much of my life it was taken for granted.
As I've expanded that gratitude to include people in all their ways, life in all it manifests and circumstances as inevitable joy, I cannot see an end to it. That is fascinating. At one point I thought I might tire of being happy and grateful, but I find that I am renewed again and again as a good nights sleep is refreshing for our energy.
So, now I agree wholeheartedly that there is no such thing as too much gratitude.