My teen is now about 38, so my info is dated. When she was a teen, and that attitude is lessening today, all on the planet was rightfully hers and any atttempts to keep her from taking possesion or control were viewed as criminal infractions of her right to have/posess it. Latest styles, car keys, vacation trips; you get the idea.
Being grateful implies that there is no right to posess so ungrateful does not really enter the consideration. It's more like dis-grateful or assuming. As an enabler of the feeling that all desired can rightfully be expected to be delivered at no cost, I share blame for this lacking.
When I was raised, I was taught to believe that all NEEDED would be delivered gratis, but those items of comfort or style that I desired but did not need would be supplied by yours truly with no help from the parental units.
I was taught to be grateful. However, as a teen myself, I overcame my teaching and forced my parents to constantly reinforce their lessons. Their wills were stronger than either Mrs. Code's or mine and I at length gave up hope of recieving luxuries unearned.
I am still quietly and happily astonished when I recieve something as a gift as I am always mindful of my parent's lesson that I am undeserving. I regret that I have removed that happy astonishment from my daughter's life. Perhaps it is something that will return for her as her own ungrateful, grasping, selfish, self centered, uncaring, unfeeling, off spring do something selfless for her.
It's the generosity that appears unexpected, unannounced and unrequested that renews my spirit and makes me feel at once loved and, once again, undeserving. Undeserving, but cared about and loved.