I think you get saddened by these types of films because you haven’t learned to control your emotions as well as your friends. I think it’s important to shield yourself from those types of sad thoughts by not letting yourself get totally sucked into the movie, tv show, or other person’s condition. Sure it’s good to empathize, but think about how ineffective you are if you can’t stop your emotions from being controlled by outside influences. If someone is laying wounded in the street, for example, rather than get sucked into their painful situation, you need to control yourself so that you can help them out. It’s something that’s easier said than done of course, and comes from persistent effort to make it a habit.

What I do to control my emotions is consciously focus my attention on something other than whatever thought is causing me to feel sad, angry, or any other negative emotion. For example, after watching battlestar galactica, I’m betting you have thoughts swimming around in your head that are similar to what you’ve seen in the show, maybe you’re even remembering some of the scenes that you saw. Instead, focus on another task, or something that’s going on around you. With your friends, focus on the conversation, a car driving by or whatever. Like the cliche says, do something to get your mind off of it.