alt Hacker NewsExternalities exist in every transaction, it just means the value created or lost outside of the transaction.
So the reason you can’t think of any is because no economic activity exists with out them.
But externalities can both be positive or negative.
Externalities are positive if you benefit from them, and they are negative if you are paying for them.
In my circles we actually never use this word because it is basically just a fancy way to say exploitation that makes capitalists feel good about them selves.