I'm feeling like dumping a girl on Wednesday just to go out with her close friend on Friday.
Why do you want to be a "bad" person?
I don't like to follow the rules, I just do what I want.
You are a rebel when it comes to rules this is true. For the girl that you dumped and her sake, I would highly not recommend to date her close friend as of yet, you can at least wait awhile for that. Rudeness is never in fashion, you can get a poor reputation and then no one will go out with you anymore.
So? I'm not going to stay single forever.
I understand not wanting the stay single. But if you go after her friend right away this is going to cause many issues. Like I said give it some time and let things blow over before you start making moves towards the friend.