When I go into a store to use a coupon, I have read the coupon at home, under two magnifiers, and memorized what it is.  Or if its a preinted coupon I write in big letters on the unprinted side.  When I get to the store I get whatever the coupon calls for and lay them out in the order I have the coupon.    I am wrong on occasion, and  will take the item anyway, My  mistake will not hold up the line.  but most times I can remember.  Today the guy laughed, as i said  ” any one, any four, any one, and any flavor”   and then I couldnt punch the keys on the little machine.  They changed machine.    He did hlep me after I explained I could not see the little buttons or the little screen.  I had it memorized.