I don’t tend to cite fictional movie characters for wisdom, but someone put on Facebook the other day a line spoken by Yoda in one of the Star Wars movies. The quote was: “Fear is the path to the dark side. Fear leads to anger, anger leads to hate, hate leads to suffering.”
I think there is much truth in that statement. Fear rises for many reasons. But often it is a response, not to an actual source of danger, but to something that is beyond our understanding: what we don’t understand we often fear.
Fear is not an easy emotion to accept. And so a not atypical response to fear is anger.
If we are sufficiently mindful, we see the link between lack of understanding and fear and between fear and anger. In the absence of mindfulness, however, all we realize is the experience of anger which, if left unchecked, can become hate. And the hate means suffering not only for ourselves, but for the object of our hate.
In the absence of mindfulness, that progression – fear…anger…hate…suffering – is, if not the, certainly a path to the dark side.
PS. My other favorite Yoda quote in the second Star Wars movie was: “Do or do not. There is no try.”
Creo en Dios! 
Have you ever been able to point out to someone how they are on the path to the dark side? How did they take it? And did they leave the path?
Waz: In general people can be taught to be more mindful. My experience is that it is easier to help people to change directions the earlier they can see the progression. (I.e., once anger morphs into something like hate, it is much harder.)