"Flight attendant for a European airline for the past six years here. I'm late to the party but I'll still chime in.
Lots of passengers panic when the flight is delayed for technical reasons or when they see the maintenance guys board the aircraft. There's really no need to be! That just means that we're aware of a problem and won't budge until it has been resolved. Much better to be aware of a problem on ground than at 36000 feet! The pilots do thorough pre-flight checks to make sure that everything is ok, 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!
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 cigs. The only real problem with e-cigs are the lithium batteries.
Many passengers see us as glorified waitresses and waiters, and to be honest we are for 70% of the trip. But we are also highly trained professionals who are able to deal with any situation on board.
There are @$$holes on almost every flight, for sure but they are outnumbered massively by nice people (depending on the destination - stereotypes exist for a reason). A simple smile and politeness will get you a long way with most crew!"