If you see mechanics running around, that’s actually a good thing. It just means we're aware of a problem and won't budge until it has been resolved. Much better to be aware of a problem on the ground than at 36000 feet!
The pilots do thorough pre-flight checks to make sure that everything is okay, and the engineers check the aircraft at the end of the day. Flying is safer now than it ever has been, no need to worry!
15/27. It is nearly impossible for turbulence to crash a plane (even the bad stuff). Turbulence is only dangerous because of things flying around the cabin and that includes people not wearing seat belts. Most accidents happen at take off and landing that's why we make you do all of those things before take off and landing.
The plane can move like a seesaw so seats nearest to the wings can have the least turbulence and seats farthest away will be the worst.
16/27. You might be surprised how much more radiation you're exposed to at altitude than on the ground.
17/27. I’ve stopped drinking coffee, tea, or any warm beverage since I learnt they use water from the water tank. Those water tanks, by the way, are not adequately cleaned and are teeming with bacteria.
18/27. Yes, smoking really is an issue on board, please please don't do it. We're all trained in firefighting but it's still extremely dangerous to do so on board. Vaping on the other hand is completely harmless but forbidden anyway, purely because it may entice other passengers to light up real smokes.
19/27. If we're in the galley with the curtain closed, it's probably because we're sitting in our jump seat scarfing down food or rubbing our sore feet, and you make it really awkward for us if you stick your head back there and ask for another Diet Coke.