Believers, If God is perfect then why does God even need us to worship him or even exist?

You're right. He doesn't need us. He is perfect in and of Himself. He created us because he wanted a relationship. He wanted to be loved by someone other than angels who worship all day as they are made to do. I know you think is what you would call "impulsive and thoughtless" but it's not. He created humans because He wanted relationship. Check out The Shack, it talks more about it in there, or you can check out the book of Job, God has a lot to say in there too about why he created other beings...