That sounds hard going Dozer, I don't think I'd be able to put up with it.
My parents have always been set in their ways. Growing up it was actually quite nice in some ways as it was very stable and predictable. Dinner was always always always at 6 no matter what, even if mum was at a meeting and we (as teens) were out for the evening, dad would still cook for 6, eat on his own (always at the table) and keep plates for all of us. We didn't have to be home at 6, that was no problem, but dinner was at 6 regardless.
They had and still have a set repertoire of meals which expanded very very slowly over the years but then seemed to reach a critical mass and could expand no more. So lasagne never made it no matter how much we asked for it - too exotic for mum. Also, mum hates rice and dad hates mashed potato - what has inspired such feelings for such bland foodstuffs I will never know, but neither of them will go near their hated food.
Dad loves spicy food and makes a fantastic curry but still hankers for the utter shit he had to eat as a very very poor child. So he makes the most disgusting stew which involves boiling the cheapest possible cut of meat with vegetables for hours until you get a greasy mush. Mum couldn't force us to eat it when we mutinied aged about 10 - she hates it herself. He has longed for tripe and drisheen (fellow Irish people will understand) for years but my mother will absolutely not allow it in the house. Bacon and cabbage is another favourite, but I must admit that is lovely.
PILs have an obsession with the weather forecast and with driving routes and traffic. Every single time they arrive they talk about what the weather will be like later that day/tomorrow (which is invariably wrong, but that seems to pass them by) and go on and on and on and on about what roads they took, what the traffic was like etc. Leaving the house is pre-empted by another in depth discussion of routes and traffic, despite the fact that there are only two routes they can possibly take and there is absolutely no way to predict the traffic.
Growing up there was always a tonne of food in my house - you could have seconds or thirds if you liked. PILs only cook the bare minimum. It drives me mad.
I think FIL has an eating disorder. It's not serious, but it is stable and long lasting - he worries terribly about his weight and often misses meals, comments constantly on my eating (I enjoy my food, but I am not overweight at all) and still mentions the fact that MIL was fat when he married her over 30 years ago (she's very thin now). I just ignore it because I feel sorry for him, I think he really struggles with food.
MIL always turns up with random food, which I then throw in the bin. This is down to my anality rather than hers really - I have bought the food I need so extra things like potatoes etc just go off, and other things like carrot soup don't get eaten because no one except MIL likes it.
MIL had a bib obsession when DS was small. She still puts a bib on him when he's at her house and I'm not around.
MIL also has a slipper obsession - where did this come from in the older generation?? I never wear slippers but every time I go to their house there's a pair waiting for me, which I ignore every time. MIL also obsesses about coats - the last time she was here she asked "Does DS have a coat?" That was a bit too much for me, and I rather rudely said "MIL are you seriously asking me if DS has a coat, do you think I didn't get him one in the middle of winter?" She laughed, but she will ask it again. She bought him a (hideous) coat for Christmas. Every time I'm at their house she tries to give me one of her coats to wear - for some reason my own coat is never good enough.