Military precision

Mrs I was so organised when I came to collect the cash and shopping list - both were placed in an envelope, the shopping list neatly folded, with the exact shop I needed to go to at the top (M&S). Every item on the list had a detailed description of what it was and the price from the last time she had shopping done for her, which made it super easy to find everything and be sure I had what she wanted. Sure enough, I bought everything on the list for the exact price pre-calculated on the shopping list - £19.80!