Have you ever eaten a sandwich with really sharp crust that cuts up the roof of your mouth? For me, this usually happens when I am eating a sandwich on a sourdough roll. Is this happens to you too, here's simple trick. Just turn the sandwich upside down so that the sharp crust is on the bottom. I know, sounds obvious. But I had never thought of this before. I friend mentioned it recently and it has change my sandwich eating for the better.