Yeah, I agree that you'll have to let it go, though I understand the struggle completely. Recently I was chiding one of my 21 year old sons friends about sending thank you (via Facebook, email, whatever... Just something!)... His reply was that he thinks just our family has expectations of a thank you, and that people shouldn't give things expecting something in return. I tried to explain to him that that wasn't the issue, but that in his case at least, the giver would like to know that the gift was even received!
Made me sad. That that really IS the mindset of so many.