Cheese!

We ask people to say "cheese" when we take their photo because it makes the corners of the subject's mouth turn up, their cheeks lift and teeth show - in other words - a smile.

In Victorian times when smiling was out and we were not to be amused, photographers apparently said "say Prunes" to make a tight pouty mouth.  According to this article anyway.

Dave made us a tasty pasta dinner, all I had to do was grate the Parmesan.