How to get what you want without being a manipulative asshole
Like I said in my note, I think that the most effective people are those who understand when to use direct, aggressive power, and when to use indirect, soft power.
However, I find for myself that people are much more likely to respect my position if I am extremely direct. I dislike playing soft power games and would much rather just tell someone what I want and negotiate from there, rather than trying to manipulate their emotions against them.
I will say that this is a skill that I have learned more in my 30s. In my 20s, I was very passive and expected people to read my mind. I struggled to recognize that most people will just continue taking from you until you say no. This lead to many situations where I was pissy or resentful, and I lost several friendships because I had poor boundaries and thought I could "nice" and "be kind" my way into having solid friendships.