There's a logical reason for keeping window shades open during takeoff and landing, which are considered the most critical phases of a flight: safety. In the event of an emergency, flight attendants are trained to look for debris, fire, or smoke outside before initiating an evacuation.

Flight attendants require passengers to keep window shades open during takeoff and landing for critical safety and situational awareness reasons. These phases of flight are the most statistically likely times for an incident to occur, and an open shade provides the crew and passengers with an unobstructed view of the outside environment. In the event of an emergency, such as an engine fire or a wing strike, the cabin crew needs to see which side of the aircraft is safe for evacuation; they cannot waste precious seconds opening shades to check for fire or water before deploying slides. Additionally, having the shades open helps passengers' eyes adjust to the outside light levels—whether it is bright daylight or dark night—ensuring that if an evacuation is necessary, their vision is already acclimated to the exterior conditions, preventing "visual shock" or temporary blindness. It also allows emergency ground crews outside to look into the cabin to assess the situation. While it may seem like a minor annoyance, this rule is a fundamental part of the "layered" safety protocols designed to maximize survival rates during the most intense moments of a flight.