Spotify Co-Founder Daniel Ek examines some of the mistakes he has made as a serial entrepreneur. Chief among them, says Ek, is saying 'yes' to everything and trying to do too much at once, which never works out. Ek also articulates the dangers of waiting too long in hiring and firing team members within a quickly growing organization. Especially in a small company, "everyone needs to carry their weight, and more," says Ek.