ungiftfull
When someone is greedy and sends you list after list of gifts they want you to buy them, say for their birthday or baby shower. The amount you will spend on their gift decreases exponentially if they are being ungiftfull.
Your sister is being ungiftfull, sending me a never ending list of things she wants me to buy her for her new baby. The more times she asks, the less I will spend. Soon She will owe ME a damn gift!