Is it because I is English?

Some pearls of wisdom from work:

"Oh look, Catherine's drinking tea. She's definitely English".

"Oh look, a sandwich made with sliced bread! Must be because she's English..."

"The till is...tired? You have such an English sense of humour..."

"There are cookies in the break room! Food from your country! Well, America, but it's all the same, isn't it?"

I try to smile. I try to take it all with le flegme anglais- a stiff upper lip (not sure how compatible smiling is with a stiff upper lip in cases not involving Botox...)

But inside? Inside I am SEETHING. Some of you will be aware of how strongly I dislike being defined by my nationality, a nationality I have accepted for administrative ease: my preferred options of 'British' and 'Catholic' (I assure you, in terms of cultural identification, I find the latter term to be more applicable than 'English') do not work in France.

And as far as my sense of humour goes, I find the idea that the entire English population has the same slightly warped and gnome-based take on things as I do frankly disturbing.