Thanks for sharing, but don't think it's unappreciated sinse nobody told you to do it and you gave it freely.
sorry, couldn't resist, but in a sense this is the point, did you actually have anything to be grateful for?
From the sound of it, no. Gratitude in it's real sense is a response to a free gift from another, a sign of respect and acknolidgement for the time, trouble, work or affection of someone else.
From the sound of it Mark, it wasn't that you didn't "learn" gratitude, it was that you were given no opportunities to practice receiving it.
The good thing is, by the fact that your hear freely sharing with everyone else, this is somethig you very clearly have! learnt, enspite of your past.