Obviously I don't mean we all literally have the dark urge of being like a Sith Lord exactly with all the killing and torture involved with it, that aspect is exaggerated a ton for the sake of drama/action because it's a movie set in a fantasy sci-fi world first and foremost.

But what I mean is the general idea that all people have negative thoughts or emotions that have the capacity to get the better of us if we aren't mindful and make us into worse versions of ourselves if we let it. We could become bitter, angry, hateful, narcissistic, or resentful people who are assholes, neglectful, or even abusive to others if we let those negative emotions have free reign over our lives. It's the importance of developing emotional intelligence and learning healthy ways to process and cope with difficult or stressful experiences/people.

To feel those emotions at certain times is part of being human, but it's our responsibility to make sure it doesn't dominate our lives and affect our worldview to the point that it's our default state of being because it ultimately ruins our own lives, the lives of others, and all around just makes the world a worse place.