The law of diminishing brownies.
You will have observed this most times there is shared food you can cut. I observed it with trays of brownies that we used to make. Slices start big and get progressively smaller. No one wants to eat the last slice.
A previous boss had a simple solution to this with a maxim he had: You think of one, you get two. A bit excessive, and I don’t advocate it, but it really did work.
Bullshit truth. For this reason, I ALWAYS eat the last one. Just on principle. Even if I’ve already had three. That’ll teach ‘em.