Warning: spent 3 years bagging and boarding comics before I noticed the flap thing
So I was at this little shop in Tucson called Fantasy Comics about two months ago, just killing time while my truck was getting brakes done down the street. The owner, Doreen, watched me flip through a long box and then asked why I always pressed the flap down flat against the back cover. I told her that's just how I thought it worked, the board goes in front, fold the flap over, tape it, done. She pulled one of my old bags out of the box and held it up to the light and you could see the crease line running down the back of the book from where the flap had been pressing for years. Turns out the flap is supposed to sit in front of the board, not behind it, so it never touches the comic at all. I went home and checked my whole run of about 180 books and maybe 40 of them had those faint lines. Doreen said she sees it about once a month from people who never got shown. Any of you ever had a shop owner point out something that seems obvious after the fact? I still feel a little dumb about it.