Well, I’ll choose the Executive branch. You have the responsibility to all the people, plants, animals, air , water and soil of your state or country that elected you AND those that didn’t. You work with the Legislative branch to form policy and are overseen by the Legislative and Judicial branch in many ways so that you do not become a totalitarian. You have the weight of you decisions impacting all aspects of society for this and future generations. You are tasked to delegate heads of departments (Cabinets) to those you feel can run them efficiently, responsibly, and in the best interest of the people. You work with other governments to realize a better Earth for all now and in the future.
It turns your hair gray though.