Great entrepreneurs aren't just product obsessed; they're impact obsessed. Rana el Kaliouby, co-founder and CEO of Affectiva, has spent most of her career thinking about how to project – and steward – the possible uses of artificial intelligence. Affectiva uses AI to read people's emotional states, but Rana won't put her software to work for just anyone. She's walking a fine line between thoughtfully nurturing her idea and being a cranky custodian: potentially throttling the scale of her business. It's a risk she's willing to take. She understands that entrepreneurship isn't just about providing a product or service that people love, or creating jobs; it's about asking: "Am I making a net contribution to society – not just right now, but for future generations?"