Someone report LW's aunt to the National Institutes of Health. She's obviously discovered the secret to immortality or extreme longevity, because she sounds at least 180 years old! That's the only explanation I can come up with for her being offended to receive a Christmas card instead of a "proper letter." Nobody sends "proper letters" to all their loved ones at Christmas, unless we're talking about the infamous "Christmas letter" that everyone gets. (Which I actually don't mind because the ones I get are newsy and not braggy.) They're called "greeting" cards, for a reason, Auntie -- they're not supposed to replace letters. Sheesh.
I briefly wondered if LW was a cousin of mine, because Aunt Offended sounds like my mom -- who was very displeased to get a 15-cent sympathy card from my brother's MIL when my dad died. (This was in 1980, so the equivalent would probably be a 99-cent card now.) But at least she only complained to me, not to the sender.