Possible Clues:

• Thanklessness
• Ungratefulness
• Inappreciativeness
• 'Blow, blow, thou winter wind / Thou art not so unkind / As man's ____' (As You Like It)
• One dating true jerks showing lack of appreciation
• Lack of thanks
• Non-recognition during alteration – a bird inserted key
• Popular opinion, it's said, about gross lack of appreciation
• I'd get in a rut working for a total lack of appreciation
• Lack of appreciation