If you have poor relationships, the quality of your code will suffer.
How you deal with people outside your team will affect the code you write.
Better relationships and communication lead to better requirements and more clarity. If you don’t have a strong understanding of the requirements, there is no way your code will correctly deliver the desired results.
Our goal as software engineers is to deliver business value by writing code. However, it is critical to remember that people outside of the technology organization are the ones who measure this value. Never forget this.