John Harthorne is the founder and CEO of MassChallenge, the global nonprofit which claims to be the world’s most friendly start-up accelerator. Named Ernst and Young’s ‘Social Entrepreneur of the Year’ in 2013, John is a Young Global Leader at the World Economic Forum, and has supported over 800 start-ups, leading to over 50,000 jobs worldwide. In this in-depth interview, John discusses why his initial business plan was ‘very unrealistic’; expresses the difficulty in finding a career that is both profitable and fulfilling; explains why he can’t ever escape being pitched to; and stresses why everyone should ‘kiss a start-up today’.