Hate is a strong word. Many people tend to say that they hate a certain person, but it takes a lot to say that you hate everyone. But what, or who, is 'everyone' to you? To me 'everyone' are the people around me. Like my so called friends, selfish fellow students at college, you get the drill.
When somebody has a good reason and say that they hate everyone, I understand them. The true colours of someone will be shown at some point, and then you will see if they stayed true for the whole time. And let's be real, most of the time, the colours aren't pretty. They can be very dark.
When you give yourself a hundrend percent to people and they hurt you at the end, you start feeling used, miserable and a lot of different things. Those feelings can transform into disliking a lot of people. Because why would you do your best when they don't? And when you confront them about their lies you wish they would man up and be honest, but they don't do it. In the end you just hate them. That doesn't mean that you have to talk to them, or talk trash about them. Leave them alone, because you don't need negativity in your life. You be you, and I'll be me, remember that.
Trust me, experience is speaking here.