In the three-minute film clip here, Madsen Pirie can be seen telling people that economics is fun. He illustrates the point by explaining how value is in the mind and not in objects as such. Questions about how things got their value are silly. Since we're all different we value things differently, and this explains why people trade, why they exchange things. I want something you've got and you want something I've got, and each of us wants the thing that the other's got and is offering more than we want the thing we've got and are willing to exchange. So both parties benefit from the exchange; both get something more valuable to them than what they're letting go of. No winners and no losers.
It's a quick, neat demonstration and to this extent you may get some fun out of it. But there's a small omission from Pirie's story: resource differentials. Situation one: you and I are both moderately comfortable property holders; you like to hear me play the piano, I like your home-grown tomatoes. So we trade. I let you listen to me play from time to time, for some agreed number of tomatoes. We're both content with the exchange. Situation two: you and I and a few other people own the island, and everything on it, which we along with still other people all inhabit. We, the owners, own everything, and they, the others, own nothing. This is a resource inequality such that the trades now open to those others will be constrained by their basic needs - food, housing etc - in a way that the trades open to us owners won't be. It will still be true that the others benefit from trading: if they exchange their ability to work (say) 12 hours a day, 7 days a week, for a wage which will just cover the rent and their other indispensable needs, this will be preferable for them to going hungry and homeless. But whether free exchanges are as unproblematically and universally beneficial will now be more open to question. It rather depends on whether the resource differentials which are the background to the story are themselves just and legitimate or not; which may also depend, wholly or in part, on how they arose.
The benefits people derive from trading may be judged not only against what would happen if they didn't trade in the same economic context, but against assessments of the justice of their differential starting points. Whether or not drawing attention to this is fun, it's a context that can be ignored only in a simple-minded view of the world. (Via.)