Why don't I get a thank-you card from my nephew?

Every week a Guardian Money reader submits a question, and it's up to you to help him or her out – a selection of the best answers will appear in Saturday's paper. This week's question I gave my nephew (currently at university) £50 the Christmas before last and didn't even get a "thank you". It was the same again this time. Are all today's teenagers/young adults so rude and ungrateful? Am I old fashioned to think that I should get a thank-you card? Should I challenge him? Or just stop giving him money? What are your thoughts?