I have learned basically to take out time every day to meditate, or read uplifting words like positive quotes, bible, inspirational books, inspirational music, or videos. You really have to take care of your mind.
For instance, I've even ignored the news for the last four years and started watching it when this bombing happen last week. It's really what you're focused on, and how does it make you feel? I can say I don't miss watching the news. It's focused on all the violence in the world, and certainly didn't like how I've been feeling the last few days after watching. So the thing is if one event affected me or caused some stress, how many other events do we watch on T.V. or shows that affect us on a daily basis? I don't watch T.V. most of the time.
I think I've learned this what ever you're putting in your mind, or witnessing does have a lot to do with how you feel about yourself, the world we live in, and those that are around us. What ever you're witnessing or experiencing causes stress in a good or bad way. While you can't avoid people entirely in your life, or co-workers you can limit amount of time you are around them if they are causing stress in abusive way.