Leaders must be the type who look at the glass as half-full versus half-empty. Why?
People need to be inspired, and they will only feel inspired if their leader is positively disposed — and joyful.
A leader inclined to be positive is one who looks at challenges as opportunities. A leader inclined to pessimism is one who sees challenges as roadblocks. One way to spread joy is let people know two things. One, you care about the work. Two, you care about them as people. That gives people joy.
Caring about them really means talking about the work, having a meaningful conversation about what they are doing, and how they are contributing. You provide them with resources and support, and you recognize them for success.
That is joyful.