DM's side of the family are not British. Negative comments that they have made include:
We have a strange way of dealing with death which comes across as cold. They find it odd that we use euphemisms for someone dying, like "passing" and how we don't like to bother people in the aftermath of a family member dying - whereas houses are full for days in their country.
We are too reserved and can't express our emotions.
They believe that we don't seem to place as much emphasis on family values, because we don't seem to have the same sense of obligation and duty. I didn't go to a cousin's wedding (who I'm barely in touch with) because it was midweek and I worked out that by being self employed/loss of earnings for three days, flight and spending money, I would have been about £1000 out of pocket, and they genuinely could not understand why I didn't value my family and also that I was embarrassing my mum by not going.
We moan about everything.
Brexit is utterly incomprehensible.
But they have also said the positives are:
We have a wonderful history and beautiful countryside.
We have a good sense of fairness and are very tolerant (although I think this has become less the case over the years).
The younger women on DM's side of the family have commented with a mix of envy and curiosity about how DP and I are unmarried and don't want kids, and how that seems completely acceptable to society.
There is a varied and vibrant culture, especially in the arts.