It's of course very easy to say we should get rid of toxic people. The reality and the ideal, however are two very different things. If you're in a group of friends there are bound to be one or two toxic people who are really nasty. At the same time, I've come to realize that a person isn't necessarily 100% toxic, and sometimes just has toxic aspects to them. People aren't just divided into 'good' and 'bad', there are too many layers for us to be able to judge something so simply.
I have a very simple definition of what makes a toxic person, and it is this : a person who just doesn't make you feel good.
It doesn't matter for what reason. Maybe that person is always trying to bring you down. Scoffing at your hopes or dreams. Trying to make you keep up with the Joneses. Laughs at you, mocks you, bullies you. You might think once you've escaped school you have escaped bullying but I've learnt, and I've seen with my own eyes that, that isn't necessarily true.
It's pretty hard to just 'dump' a toxic person. What if that person is in your family? A really annoying relative that you're forced to constantly see. Someone who's in your group of friends. Dumping a person might lead to you dumping the whole group, if you're trying to run away from that person.
I usually operate by phasing myself away from a particular toxic person. If a toxic person exists within a group, I sometimes do just miss total outings. You may say this is silly, but I measure how much happiness / anger a particular outing is going to cost me, and if I know I'm going to be walking away angrier than happy, then I rather miss out.
What I have found most effective though, is not focusing on my hatred of toxic people, but surrounding myself with nice, genuine people. While it's not easy to find a lot of them, you will always be pleasantly surprised by people if you give them a chance - especially people you might not have thought you could have connected with.
Sometimes we fall into the trap of being with toxic people because we simply fear being alone. While it's not easy being alone, I always maintain that it is better to be alone than be with the wrong people.