I guess I shoulda known by the way u sliced your toast sideways

When growing up it is easy to assume that everyone does it (whatever "it" may be) the way it is done in your family.

In my childhood we drank tea out of mugs. We may well have had cups and saucers but I do not remember using them. Long after I left home and found my way in the big, wide world I would regularly find that I had put my cup down on the table. I would then hurriedly replace it on the saucer before anyone noticed.

Similarly with toast. Either eaten whole or, if cut, sliced horizontally into two rectangles. When I started staying in hotels I assumed that diagonally sliced toast was some kind of catering affectation. It is much harder to spread the butter and marmalade into the triangular point than the rectangular corner.

Then I met our friend Kate who I think of as a bit "county" and she cuts diagonally thus reinforcing my sense of being lower middle class. Horizontal slicing is obviously Non-U.