I think I'm just a greedy guy.
What brought you to being so greedy?
Well, I was raised to be this way.
You are an adult now, you have the power to change all your bad habits. Being raised like that is just a lazy excuse to keep doing harmful things to others, and it's immature.
But how do you expect me to change my ways?
You need to introspect yourself and analyze your emotions constantly. There are tons of self-help book in the market to help people change their habits. Get a one or two and see how it works.