"Are the witches out there?" Ms. F asked. "Oh, yes they are!" I said, and I knew I was one of them.

I knocked at Ms. F's door on a Halloween night dressed as a corporate witch. Kind of. My costume wasn't too amusing, so I didn't get any treats, although Ms. F offered me water.

No treat, so what was the trick? The lady sent me to Waitrose to do her shopping. I found almost all the items, some already low in stock. All baby brussels sprouts were already reduced, so I went for the grown ups with longer expiry date. The six-packs of Buxton still water were sold out, so I outsmarted Waitrose by buying six single bottles for Ms. F. That was the trick.