When you can't see for looking...

Recently, a friend and I nipped over the mountain to the hills of the Constantia vineyards for a walk back in history at Groot Constantia. After partaking of a leisurely luncheon, the time came to pay the bill and I reached into my bag for my wallet. This bag has many compartments and is multi-zipped for additional security. The wallet also has many pockets and places for cards. I had stopped earlier at a supermarket for some essentials and had used my debit card, but as is our way, paying is an automatic response procedure where you take the card, put it in your bag, sign the slip, put that in the bag, then leave.
I searched every pocket of that bag, every compartment of the wallet, zipped and unzipped everything that had a zip, searched through everything again and again. I searched through diaries, notebooks, piles of receipts, folded up tissues, my jeans pockets, the wallet again - to no avail. And try as I might, I couldn't remember if the cashier had handed the card back. I break out into a little sweat when a card goes missing, not because I fear that someone will hack into my account and withdraw thousands of Rands (no chance of that! - they would be sorely disappointed), but because I fear I have lost my mind as I cannot find it or remember the chain of events. Alzheimer's looms large on the horizon.
My friend sent her husband to the supermarket to find out if they had found the card while we drove back to the mall to sort it out at the bank. When we pulled into the vast parking lot, by an amazing coincidence we turned into the exact same parking space as I had been in earlier, so I scouted the area and asked the car guard if he had seen it, but of course he had no idea what I was talking about. A discussion with the manager at the supermarket revealed nothing and by that time the bank was closed, so as soon as I got home, I phoned to cancel the card.
I emptied the bag and threw out all unnecessary items. I opened my wallet and removed every single thing from each compartment and threw more unnecessary scraps of paper, business cards, appointment cards, shopping lists, a TV licence and two paperclips into the bin. I then shook it upside down just to clean out the crumbs that seem to gather in the darkest recesses - and the debit card fell out.
I have to say that I once lost my credit card and two weeks later found it in my handbag, which I had also searched with the same thoroughness. I am now going to whittle down the things I carry with me to a wallet with one line of cards, one zip compartment for coins, and one pocket for notes. The bag will have one pocket for lipstick, mirror and comb, and the big space will be for the wallet. But then where will I put the diary, notebook, pen, tissues, cellphone, pocket knife, small screwdriver, toothpicks, waterless handcleaner, fold-up shopping bag... I have tried a bag organiser, but I need a bag organiser for the bag organiser.
If anyone has the solution, please let me know. Otherwise I will have to come back as a man in my next life and just keep it in my pockets.