Are they (post-)soviet boomers? There are some cultural things that I noticed too, some amusing, some frustrating.

• Home food is automatically better than restaurant food, as you said. Also, somehow, any burger is automatically viewed as McDonalds burger (i.e. bad)
• Unsolicited advice and unprompted attempts to help.
• Insistence on getting you a gift or accepting a never-requested gift. “Here’s a nice thing, it was expensive and difficult to get, you should like it”.
• Viewing self as “a burden”. Being offered food, comfort, or accomodation is rejected because “I don’t want to impose”. Sometimes goes into “suffering builds character” mindset, which is nonsense.