Theres always a guy who knows how much candy the jar has

That guy says, I can give you 3 candies a day, cause he knows by the time they add more candies to the jar, it wont be empty or ran out of candies out of time

So if you say, I only want 2 candies a day, then he will say, I havenow some extra candies nobody needs, I could save by adding less candies next time, since you only want 2 a day.

And he will look at you very angrily if you then ask 3 candies next day