There was a time, not too terribly long ago, that I would allow these kinds of people to rule my world. By rule, I mean, control my emotions. For whatever reason, I felt personally attacked because of their negativity. I would question everything in my world, simply because of something that was said by another. This is where I went off course.
The most important thing that we must all realize in situations such as these, is that negative people will not bring anything positive to the table. The only way to deal with them in the now, is to put them in the "then." You can not allow a person's negative vibe to influence how you feel, act or otherwise interact with other people and situations in your life and trust me, they will IF you allow them to.
I've had more than my fair share of negativity in my life. I have learned to recognize the signs. When people make me question my own intelligence, my own motives, my own sanity, simply by talking, then I know that it's time to remove them from my space.
If you allow yourself to be upset by the actions of others, then you are doing exactly the same thing that they are doing, bringing negative energy into your life. Take a deep breath and find another way to vent your emotions. I work with prayer. It drives me in a different direction and away from the negative place that I was heading in.
Another thing to always remember is this, while you should try to put a positive spin on any negative situation to try to turn it around... not all situations will turn. Realize it for what it is. Some people are, in their minds, never wrong. No matter what you say or do, there are some people that are so self consumed with righteousness, that you will never be able to bring their attention to their obvious negative nature. Put it and them away, and focus your attention on yourself and pulling yourself back into a more positive atmosphere.
Put away negative people, by surrounding yourself with positive people. You will know which is which by how they make you feel.