This.
My best friend since childhood (we're now almost 40) has 2 teenage daughters. One is the sweetest, kindest girl you could imagine. She always contacts me to say thanks for gifts (birthday and Xmas). The other daughter doesn't even acknowledge gifts I send for her. This has been going on for years and it's really starting to upset me. This girl (the one who never says thank you) is always rude and disrespectful in other ways. Shows no manners whatsoever.
WIBU to stop buying for the rude, ungrateful girl and just but for her sister?