A gift post on the E board made me think of this. I would post this question there, but I didn't want to sound like an idiot, and they can be a little scary.

If someone only gets you a card and writes in it (not that there is anything wrong with it) do you send them a thank you card for the card? What about for birthdays and Christmas and such? Usually I just call and thank them for the card (birthdays), but one time I sent FI's grandparents a thank you for their card, since I knew they were big on stuff like that and I knew they would appreciate it. FI made fun of me for it.
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