It goes back to my childhood. I have a sister 5 years younger who liked to copy me when we were kids. So, I got in the habit of telling her what I would order and then "changing my mind" after she ordered.

I can usually count on a taste of Mrs BamaVol's meal since she can't finish an entree most days. I'll offer a taste of mine. She'll resist unless I insist. We do split a dessert most times if we order any.