There are reasons behind those annoying airplane rules. We all have a misconception that flight attendants like to act like your mother or your 4th grade teacher when you're just trying to relax on a plane. Some feel they are on a power trip or like to nag. However, there are some reasons behind those annoying airplane rules.
Because if there is a need to evacuate the aircraft you could be trapped behind your tray table and would need additional time to put it up, latch it and get it out of your way. Even if you do manage to squeeze out from behind your tray table, what about the person next to you trying to get out? Safety is just one of the reasons behind those annoying airplane rules.
Not necessarily for your own safety but more for the person behind you. No one cares if you sleep through takeoff and landing. That won't hurt anyone, but you never know when a few inches might make the difference between the person behind you being able to get out of their seat and into the aisle or not. So again. Its for evacuation purposes.
Because you and the other passengers in your row could trip over it during an evacuation. So you may want to think twice before hiding your bags behind your legs while seated or wrapping your purse strap around your feet while your purse is down there. Its all about clear aisles for your safety. This is especially enforced if you're in an exit row. You would be blocking one of the most important egresses in an emergency.
Not really for any internet connection interference or any technological reason at all. It's because of the size of the laptop. All related to evacuation. When you are running for your life you may be hindered by a big item and especially one where you'll be tempted to take an extra few seconds to close the lid then try to get rid of it from your lap in order to get out of your seat quickly. That is why you are allowed to have your phones or Ipads out - because they're not as big as your laptop.
Such as up until you hear the first chime after takeoff and then again at the 'prepare for landing' is because this is the 10,000 feet mark. This means you are above 10,000 feet at the beginning of your flight and going below 10,000 feet at the end of your flight. This is the crucial phase of flight. Meaning if something were to go wrong, statistics show it usually happens either during the first 10,000 feet or the last 10,000 feet because that is when taking off and landing procedures are happening and there is more chance for error or danger.
So the next time your flight attendant asks you to do certain things, maybe she will sound a little like your mother because truthfully it is for your own good ...well, your own safety in this case.