This passenger didn’t quite get the memo about how flights work. We’re thankful that at least they’re sitting on their seat, not across anyone else’s seat. They probably didn’t realize it looked a little strange to sit upside down, or that other people were surprised.
Maybe we’ve been sitting wrong on airplanes our whole lives, and it’s more fun to sit that way. Who cares about airplane etiquette anyway or how the other passengers feel. Or else it’s a new trendy airplane yoga exercise, and we’re the last ones to know about it.