Well, with holiday gifts you have a couple of outs. If it is the wrong size, you can return it and get something else in your size. There is the possibility that the store is out of the ugly sweaters, or your local store in the chain didn't carry it so you are forced to exchange it for something a little less horrible. Most people just lie and say it was lovely, and wear it while the giver is visiting and then stuff it in the back of the closet where it will be forgotten. There is a chance though, that you really don't want to lie to your in-laws, even a little white one. In that case, the day before they arrive, drop the sweater at the cleaner. When they show up, thank them for the gift and express your heartfelt thanks for their generosity. Be sure to add a lot of phrases like "You are so thoughtful" "I can't thank you enough" and "You have such a unique eye for gifts!" so you don't actually have to say "It is a beautiful sweater." If they ask about the fit or the color, say it was just perfect. Sure, you meant it was just perfect for a really ugly sweater but you don't say that part out loud! Then you can add the clincher... "I'd put it on to show you, but I'm afraid it's at the cleaner!" This does 2 important things. 1) It suggests that you wore the sweater so often that it needed cleaning and 2) it suggests you love it so much you went to the trouble of having it dry cleaned.