My late mother-in-law used to tell the story of how one time when she made tuna casserole, it came out noticeably better than ever, which was puzzling, since it was the standard recipe from the red plaid Better Homes & Garden cookbook she always used. The whole family told her how good it was. After dinner, as she was cleaning up, she found unopened the can of tuna fish she’d forgotten to add to the mixture.