User Experience and industrial design sometimes isn’t about A/B testing. Yet, it still has a ridiculous return on investment.

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But as it turns out, the iPad's appeal is more emotional than rational. Once you get it in your hands, you get caught up in the fascination of manipulating on-screen objects by touching them. Apple sold 15 million iPads in nine months, created a mammoth new product category and started an industry of copycats. Apparently, it doesn't pay to bet against  Steve Jobs's gut instinct.

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My friends, I'm telling you: just that much improvement in thinness, weight and speed transforms the experience. We're not talking about a laptop or a TV, where you don't notice its thickness while in use. This is a tablet. You are almost always  holding it. Thin and light are unbelievably important for comfort and the overall delight. So are rounded edges, which the first iPad didn't have.