I explained that that was actually untrue, and explained the crown glass method, and that a small percentage of those panes are thicker at the top. He just gave me this scornful glance and said "I've got a doctorate in chemistry, I think I know a little bit more about this than you do." I was so mad! No, dingus, you don't. You study membranes, and you've never read anything about glass. But I didn't want to start a fight, so I had to just let it go.