The story goes that software engineering is about knowing how to design a system a build it.
The truth is: you also have to know how to _sell_ your design, how to document your decisions, how to push forward with your agenda. You won't go anywhere without a team that values you. This means that interpersonal and communication skills should be valued much more than what I thought they'd had to be.
The most important part of a person is their relationships (you're not convinced? Try this exercise: describe yourself without mentioning any single relationship or its effect on you. What remains?). This is true both outside and inside your job. Value building strong and good relationships.