DD is nearly 2 and whenever anyone from MIL's side of the family gives her a small gift/money as a present, in spite of me thanking them in person for it at the time, she tells me later I must send them a 'thank you' card as well.
I'm 40 FFS! It wouldn't be so bad if she gently suggested it (although I think a verbal 'thank you' for a small gift should be enough?) but she tells me to send one like I'm a child, which is what is really pissing me off! 
I know it'll happen again in the next couple of weeks... Obviously, 'thank you' cards were sent to everyone who gave us something before and after DD was born, but this is getting silly! I'm not being ungrateful - I do thank everyone at the time!
GRRRRR! 