“I want to become a successful, creative, fulfilled person in the future, and your behavior doesn’t align with my vision. I wish you the best, and I thank you for being a part of my life, but we can’t be friends anymore. I’m not sure who I will hang out with now, but this is what I need.”
This a perfectly reasonable conversation to have with a friend, whether real or imaginary.
[Here’s Breaking up with your friends, part I.]