What does happiness at work mean?

Alfonso de la Rocha:

Workers all had clear missions, see their jobs as a challenge and a means to reach their personal goals. This motivates them to wake up early every day, and happily go to work. A mission can range from “building a passive income to be the owner of my time” (personal), to “curing malaria and putting an end to hunger in the world” (philanthropic), or “building a new payment system to make people’s lives easier” (social, professional). These missions may be completely personal, or they can be aligned with your company mission. What is clear is that the happiest people at work I have ever met all had a clear mission, or at least where aligned with their company’s mission.