Alice and Bob both love Banana Ice Cream, they visit Charlie at the local cafe to indulge in their favourite treat together.
Unfortunately, Charlie has sold out of Banana Ice Cream (thats a fib actually, he loves it too and has eaten it all).
Alice and Bob cannot have their beloved Banana Ice Cream and are sad, however Charlie is their friend so wants to help (that a fib too actually, he is just after their money to feed his Banana Ice Cream habit).
Charlie tells Alice and Bob what other treats he has that they may like, he lists other Ice Creams, Tarts, Pies and Cakes.
After some thought Alice chooses Strawberry Ice Cream - because it isn't Banana but at least it is Ice Cream. Meanwhile, after some thought Bob chooses Banoffee pie - because it isn't Ice Cream but at least it is Banana.
So in the end everyone is happy - even Charlie because he short changed them both and can afford enough Banana Ice Cream to last a week.
The moral? Just because two people have the same first preference, don't make assumptions about what else they may prefer.
The other moral? If someone wants to deny you something, there maybe reasons they don't want to tell you about.
Final tip: Always check your change before leaving the counter!