Another thing. Arriving at the gate 15 minutes late only having to further delay departure because there are still people showing up at the last minute, usually with two duty free bags plus the odd coffee/big mac in their hands is usually quite annoying. I has always amazed me that in the case of a delayed inbound aircraft, still the odd passenger on the next flight almost manages (and often does manage) to miss it, even though you would expect them to be standing ready to board at once by that time...
If you're a frequent flyer you get sick of being herded like cattle by the likes of Ryanair and Easyjet well before the flight's due to take off. I'll always check the Arrivals board and go down as the plane's due to land, hopefully not having to queue at passport control which would mean missing my Speedy Boarding privilege (which often means Fatso chooses you instead of you choosing to avoid him, but that's another subject). But some people clearly cut it even finer than that. I'd say if you've not got checked luggage it's very risky, otherwise you should be fine though I don't condone it.
Re watching the safety demo, I'll only look up if I feel the attendant welcomes it and isn't embarrassed about being oggled by lots of people with no interest at all in what he/she's actually doing. And when they have to blow into the whistle I find it very hard to maintain eye contact ...
