Ungrateful (adjective)

1. Not feeling or showing gratitude for kindness or benefits received.
2. Displeased or discontent with what one has received.

Origin:

Late middle english: from un- (expressing negation) + grateful.

Examples:

1. She felt her son was ungrateful for all she had done for him.
2. The ungrateful employee took the credit for someone else's work.
3. The ungrateful recipients refused the gift.
4. The ungrateful patient was never satisfied with their care.
5. The ungrateful child complained about the toys they received.