I think I'm a manipulative person. I want to be better.
What exactly do you mean by that?
I wanted to see what will happen if I manipulated people.
That's a terrible thing to do to someone just to see if you can.  Manipulating other people is wrong and will eventually lead you to not having anyone like or trust you.
Is manipulating people really that bad?
Yes, it can lead to emotional stress on the other person. They would have a hard time not only trusting you but other people in the future so make sure you do stop.