Can't! Lets put it in simplistic primary school mathematical terms for you shall we.
Let's just say that Mr Manic Organic has 10 falafels left & there are 10 customers in the queue. Customer 1 & Customer 2 are having a party with all their veggie mates & want to buy as many falafels as they can but Mr Manic Organic says "No! Fair's fair, you can only have 2 each". So that leaves one falafel each for customers 3,4,5,6,7 & 8 but then all the falafels have gone so customer 9 & customer 10 have to make do with flapjacks from Mr Tiny Teas instead.
The next day the same thing happens again. 10 falafels, 10 customers. Again customer 1 & customer 2 want to get their greedy mud caked paws on as many falafels as they can & this time Mr Manic Organic isn't quite so strict & allows them 4 each. So now there are only 2 falafels left for the remaining 8 customers. And horror of horrors the Tiny Teas Tent burnt down overnight so there is no fall back option for the unlucky 6.
Now lets imagine that Customer 5 is one Lord William of Walworth. Under scenario A Lord William gets his falafel & is very satisfied with his purchase as it is the best falafel he has ever tasted. Happy days!
But under scenario B he goes HUNGRY!!!