system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do all airplane seats need to stay upright during takeoff and landing?
gpt
Take-off and landing are the most dangerous part of any airplane ride.

As such, precautions are taken so that if the worst case scenario happens and something goes wrong during take-off/landing, we minimise the damage. Being upright and locked into place, means the seats are better at absorbing shocks and people can brace for impact. Trays and loose items are stowed so they can't turn into projectiles. Having your seats upright also means that if they do need to evacuate, everybody has enough room to get out of their seat. Evacuations have to happen quick and efficiently, and that can't be done if someone else's reclined seat means you have trouble getting up from yours.