Have you ever held a knife over your lovingly-prepared peanut-butter-and-jelly or ham-and-cheese sandwich, and then couldn't decide which angle to go at it from? Here I make the case that diagonal cuts are superior.
With lengthwise cuts, there is no clear line of attack when your mouth approaches the sandwich, since it results in slices of equal width their whole length. Horizontal cuts have the same problem, plus they result in a grossly asymmetrical sandwich, which is just uncalled for. Diagonal cuts, however, provide skinny ends for easy eating, which eventually lead to the glorious overstuffed middle; this means less mess and a grand finale.
