The difference between a hobbyist and an entrepreneur, as illustrated by a con interaction with a fellow vendor.
Vendor, a hobbyist: "Do you want to swap books?"
Translation: "I want your book but I don't want to pay your price for it, but I'm willing to lose the cost of a book I paid for it, and also shove my own stupid book that may or may not interest you into your face."
Me, an entrepreneur: "No thank you."
Translation: "No thank you." #cosowriters #WritingCommunity

If I said yes, I'd not only lose the cost I paid for my book, but I'd have to reorder it. Thus I've lost the cost and potential sale value of two books while only gained someone else's book, that I'm unlikely to read because I only consume audiobooks these days (I read like an editor, which makes enjoyment difficult). Also, if I wanted that person's book, I'd ask about it's availability in my chosen medium and would buy it with my funds, not company funds.

If somebody challenges me ("Why don't you want to trade books?") I explain this to them, and it often opens their eyes. I love #writing, and I love getting to share my books with people, but I also have a business to run and a business must turn a profit or else it's...just a hobby.