When I recieve a thank-you card, all I feel is the achy fatigued hand of the writer, who just threw another dabbled off form letter into the mail, facing yet the hundreds more he still has to write.
I actually just gave a present to a Bar Mitzvah boy, and I wrote on the card “Included in this gift is my mechila of the thank-you card, use the time to shteig veiter!”.