"The universe exists only in my own mind, none of you are real."

You are selling this idea short. I drew a lot of wisdom from this realization in my younger years. The fact that your own existence is an irreducible certainty in a world of vague approximations is the ultimate argument for individuality, and leads into the realization that anything which arbitrarily seeks to limit your autonomy is evil. It inoculated me from many pathological ideologies in my youth.