Trading. Its era's economy in a sense, and the most common activity done on average. But why do people trade? I view it as this; people buy an item. They should be satisfied with the item they purchased and not sell it for another. Why people do it? Here's your answer.
AsapSCIENCE, a YouTube channel, made a video saying that money can buy happiness. Now in Era terms, we will use items instead. Getting an item makes people feel good. We, as humans, are adaptive to change. People enjoy change, and some despise it. But what does this have to do with happiness and recieving an item? Well if we get scientific about it, this is how it goes down. Getting an item might be a good experience, which can cause your brain to release a chemical called dopamine. Dopamine is what makes you as a human feel "good". Feeling good can be triggered by being with the one you love, having a fun experience, or in bad cases, using a narcotic. An item triggering that feeling may feel good for a little, but soon it will fade.
So can money, or in this case, items buy happiness? In a short time case, I think I'd say yes.
~Enzosthename McHatin*