This clip wonderfully shows the effects of feeling understood about a passion—that is, a powerful emotion. You see how cathartic it feels for the person sharing the passion and how important it is for someone leading the person.
Context: In a long interview, Dustin Hoffman is talking about the challenges of growing up under a stern father and how he escaped through movies, which evolved into acting. He starts to talk about how his exploring and understanding his relationship with his father and unexpectedly realizes he is revealing something deeply personal about his preparation for that role.
What to look for: When he realizes the depth of what he’s revealed, try to gauge his emotion. Would you say he more likes or dislikes the feeling?

I believe he likes the feeling. He looks to me like he likes getting it off his chest, not trying to hide it, like anything else would beat around the bush for a deep passion.
To consider from a leadership perspective: Imagine trying to direct him without knowing this passion of his, that the foundation of the role is his relationship with his father. I can only imagine directing him without knowing his passion would be fruitless and frustrating to him.
Those who don’t understand the role of passion and strong emotion at work or wherever they want to lead could say that in acting and drama people are supposed to share their feelings and passion, but not there. I find people love working on things they care about, if their leaders and managers respect and support their values.
I suspect most people in leadership positions who don’t elicit their followers’ passions and support them for them are like people trying to direct Dustin Hoffman without knowing he’s using the role to explore and understand his relationship with his father.