I always prefer an aisle seat but the person in the window gets to decide whether the shade is up or down. And more often than not shades should be closed.
Window shades as well as cabin lighting get adjusted for takeoff and landing for safety, to improve reaction time of both passengers and crew. And when you land in a hot city you’ll often be asked to close the window shades before getting off the aircraft, to keep the plane cool for the next flight. But what about when you’re in the air, mid-trip?