"Dear Old Person. Thanks for the Loot."

Insincerity is not something I am good at. I've tried to learn how to use it effectively, but I have never been able to be convincingly insincere. Try as I may, I cannot make the "Love" with which I sign my thank-you notes to sound true. I have ranted about this before--the time-honored tradition of beginning letters with the phrase, "Dear Name," whether or not that person is dear to you or not. I cannot handle the insincerity of it. Every time I write a thank-you note to someone who demands them, a someone who is, unfortunately, not dear to me, I have an inner turmoil of insincerity, and I wish I could say, "Thanks, you old bat." Although this would be a much more satisfying way of opening the note, its effectiveness would be in question. The note in question addresses the gift of a book called 1001 things every teen should know before they leave home (so they don't have to come back). I do not mind the book so much as the implication that I should get out of the house and leave my parents alone. If the advice in the book were more than just common sense I wouldn't mind either. However, the book has 1001 little bits of advice such as, "Sex makes babies." No duh! "Pay your rent or you'll get evicted." Really?! "Don't get married until you're rich." Which is total B.S. The book is an annoying mix of preachy and trying-to-be-hip. Therefore, after my initial flip-through, I have not looked at the book, and have instead been using it as half of a laptop stand. I mention it merely as useful.
I would not mind the thank-you note thing if it weren't so mandatory with this one particular person. If you forget to write a thank-you note, even if you have as valid an excuse as you're drowning in homework and extra rehearsals, the party in question will pester until she has a thank-you note in hand. This pestering, although it works with some people, is resulting in fewer and fewer thank-yous from the busier members of the family, later and later thank-yous from the less busy, and more and more insincere thank-yous from everyone. I'm not so good at the insincerity thing. I might drift into the non-senders group, which becomes the non-receivers group. I'd almost rather have nothing than to lie repeatedly.