Isn't an economy specifically about optimising resource allocation. The more general term being a financial system.
I assume you're being purposefully terse, but just in case ... can you see how one might want to do an activity without considering 'could I charge people [more] to enjoy this with me, could I end this activity with less opportunity cost lost' and instead just be generous with something one loves and free with ones use of time when having fun?
An economy is any system that involves the production, consumption and trade of goods. It’s simply a way of describing and analysing natural human behaviour. An economy doesn’t have to aspire towards any form of efficiency, it doesn’t have to involve money, or any form of payment. It doesn’t need to be governed, or subject to any form of authority. It is simply what happens when you have people consuming or utilizing anything that was produced by another person. The only way you could exercise a passion without any economic interactions is if you did so entirely by yourself, without the use of any goods or services produced by another person, and without sharing any of the value you may potentially be creating with any other person.
I assume you're being purposefully terse, but just in case ... can you see how one might want to do an activity without considering 'could I charge people [more] to enjoy this with me, could I end this activity with less opportunity cost lost' and instead just be generous with something one loves and free with ones use of time when having fun?