The diagonally sliced half is optimized for dipping in a variety of soup containers.
Mutual support in a vertical setting maintains overall structural integrity in the hours leading up to lunch.
Hypotenuse length maximizes tongue-to-sandwich-filling contact area.
Longer fissure span means increased chance of creating a melted Cheese Bridge.
Triangle structure creates an obvious grab zone.
Acute corners allow for four perfect initial sandwich bites.
The initial corner consumption sets up two ultimate bites of unmatched, crustless perfection.
Please submit any rebuttals below for peer review.