"I prefer guests with manners, so it seems neither of us is getting what we want today", then change the subject and talk to someone else.
Most of my lot are feral in some way but they tend to at least not do things that are offensive to anyone particular.
My mother, who I love wholeheartedly, can't ignore a fault in something - never picks fault with something like cooking or someone's presentation of something, but let's say a cheese said it was strong flavoured and doesn't entirely blast her socks off - several hours of occasional 'well I don't know, apparently my taste buds have packed up' type comments.
Dad can't just sit and relax, he'll find something to tidy, put away, rearrange, prepare, check on, stir, or plan for. Or fall asleep.
DH will either decide something fucking bizarre needs doing NOW on Christmas eve while we're trying to get everything ready for Christmas day (cleaning the gutters or resealing the bath), or he'll loudly point out something we missed while cleaning once the house is full of guests. And yes, that does include the bits he cleaned himself.
One of my uncles will tell us he's working or on call, promise to drop in if he can after 4, then turn up halfway through dinner and insist he's not hungry and go and sit in the living room on his own until we've finished.
And MIL goes full Mrs Doyle. 'Can I get you a drink? Are you sure? I could make tea. Or open a bottle of wine? Are you sure you don't want tea? It's no trouble.' And if you say yes to tea just to make it stop? All you do is open the door to the biscuit selection and whether you just want a biscuit or are you hungry? Because if you're hungry then I could make sandwiches...' 😆