It's polite to share food with others if you can.
Colby is in the break room at lunch eating when he realizes that Jed doesn't have any food.
Colby wants to eat his food.
Colby gives Jed half of his sandwich and buys him a bag of chips.
Colby eats all of his food in front of Jed without offering him any.
Jed is able to work better through the rest of the day with a full belly.
Jed is hungry and gets distracted and is generally unproductive with his work all day.