And here is why: Uber and Square both change the transaction interaction. (Apple and Amazon have done so, too, but not in new places arguably.)
Uber addresses the awkwardness of paying for a cab or car ride. I have always felt anxious around these moments: the ride is over. I want to get out. The driver wants to get a new customer. Yet we both must wait and, if I'm paying by debit card, there's the tension of whether or not the driver will accept a card (even though it's legally required in Chicago). I hand over my payment, I'm asked for tip (and I need to know what's appropriate!), and it's just all very pedestrian. Uber has made this process so smooth that it barely happens.
With Square, I simply walk into a store and order what I want. I confirm I'm paying by saying so. And that's it. No muss, no fuss, no money changes hands.
Both are brilliant in their own ways, and both make me feel like I'm living in 2013 for real. I might not have a jetpack or a hoverboard, but I have a way to purchase things without using money, a plastic card, or a piece of paper. Pretty nice.