For me a solid, productive Sunday sets me up for the week. 
Meal planning, dishes, laundry, outfit planning, goal setting, inbox zero and any admin I can take care of to set myself and my team up for a strong Monday, plus reinforcing and practicing healthy habits. 
When I don’t get through my Sunday routine my week suffers. 
You might think it sounds like work, but I consider it a gift to my future self.