Sandwich Envy
A mental condition similar to Freud's theory of penis envy; however, sandwich envy is not strictly limited to females. Sandwich envy occurs when one person has access to a delicious sandwich, and his/her friend(s) do(es) not. Symptoms of sandwich envy include hunger, jealousy, and apparent staring at the person with a sandwich. Thirst sometimes accompanies hunger, but this phenomenon is a rarity. Similar conditions exist with other tasty foods.
Person A is eating a sandwich during summer school break, while A's friends are watching. These friends suddenly feel hungry and are jealous of the sandwich-eater. They are encountering sandwich envy.