I've got three examples that shine out - have mentioned one of them before but is worth re-telling.
When DP was married to his ex-w they (and their 3 dcs) went to stay with her brother and his wife and 3 dcs for Christmas. They'd driven some 300 miles to do so, arrived on Christmas Eve and all had a thoroughly pleasant evening. On Christmas Morning, dp's then SIL got up, made herself a breakfast tray and took it back to bed from where she announced she was "thoroughly bored with Christmas" and would not be coming downstairs again until Boxing Day.
Unfortunately, her boredom with Christmas had clearly emerged a few days earlier since it was discovered that the cupboard was surprisingly bare. As a result, DP and his then BIL spent the rest of the morning visiting such local cornershops as were open to put together a rather unique Christmas dinner. On Boxing Day, SIL re-emerged and behaved as if nothing had happened.
The second tale concerns a former boyfriend whose parents we went to lunch with. Rather to my surprise (given that his mother was obsessional about housework) their budgie was allowed to fly free during lunch and made several not very stealthy bombing raids on our dinner plates. It finally nested on top of my head (I have to admit that I am not wonderful with birds) and when I asked (very calmly) my boyfriend if he could perhaps remove the budgie, his mother said "Poor Joey, does nasty Pandemoniaa not want to share her dinner nicely with you?"
And finally, in the days before we had any dcs, we were invited to tea with a friend whose parents lived 200 miles away and who he (a teacher) was spending his holiday with. We (me, ex-h and 2 mutual friends) were en route to a boating holiday and teacher friend (tf) insisted we pop in for tea. He kept assuring us that his mother's teas were "famously lavish" and that the table would be "groaning with lovely home made cakes". So insistent was he that it seemed impolite to refuse.
Except that when we turned up (as pre-arranged!) she gave us an extremely baleful look and reluctantly admitted us to her pristine front room. We were told which chairs we were allowed to sit on - "not, there, that's Daddy's Chair!" and with a suspicious glance, she returned to the kitchen having summoned tf in with her. We were then treated to an argument about Eccles cake "they are to have half each or I'll have to bake another batch" and that we were not to be given butter in the sandwiches or "they'll eat them all". On being allowed into the, equally pristine, dining room we were presented with a beautifully laid table that contained very very little in the way of food. Most of it might as well have borne little "Keep Off" labels. Conscious of Ecclescakegate all but one of us treated them as if they'd been laced with anthrax. However, (tf) pressed us to "dig in". So one of us did and praised their deliciousness. Worse, he went back for a second! TF's mother then turned to him and said "Presumably you've got Southern manners. Do you eat like a pig at home too?"
We made our excuses fairly shortly after that and left. "Have an Eccles cake" remained a cue for hilarious laughter for many years afterwards.