You will interact with several different types of people as you move throughout life. These people will have different impacts on you that will range from a bare minimum to possibly life changing. I don't believe that everyone you meet makes an impact on your life, but everyone you interact with for long periods of time will certainly affect you. The real dilemma when thinking about these people is how to deal with the ones who negatively affect you, as well as when to step in when people are negatively affecting the people you love and care about.
Obviously, when considering confronting the people that are toxic to you, you still have to be somewhat level headed and mature about the situation. This means no screaming to get your point across, no throwing things or anything of that sort. Before a few years ago I honestly thought all of that stuff just happened in movies. I still don't understand why anyone would do it, it's a childish act that doesn't make any progress. It might make a ton of regrets, but that isn't the goal.
When dealing with people, the easiest and most logical route is to approach them and let them know what is bothering you. Sometimes, you get unlucky, though, and have to deal with people that either won't listen, won't stop and pay attention or won't take the criticism easily and will make a big scene. When dealing with people like this it seems easier to just stuff your problems in the back of your mind and figure that that person will eventually be out of your life.
In truth, no matter how irrational the person who needs to be confronted may be, it's always better to speak in a calm way rather than being pushed so far past your limit that you become the one to raise your voice. It's best to write your points out in a list and organize them so that you don't forget to speak your mind about some of the not-so-obvious factors that still make your life hell.
Let's say, for example, that you don't get there and the worst case scenario happens: a screaming match throughout the day. After you've said what you've needed to say, just cut that person out of your life. You are better off without them, make the choice that is best for yourself so that you turn out to be a healthier person at the end.