Well I'm just a passenger, a fairly frequent one, and it's my personal opinion that your ARE stupid if you don't:
1. Read the safety card;
2. Observe the cabin crew's safety briefing;
3. Check how you personally would leave the aircraft in an evacuation. This perhaps means nothing more that counting the number of rows between yourself and the exits.
4. Listen to the crew's instructions if an evacuation should happen.
In any case, items 1 to 3 should take no more than 5 minutes. When you might have an hour, and likely much more, to kill between departure and arrival, how hard can it be?
This discussion would be a lot more productive in another forum like SLF.
Imagine the pilots not reading their safety instructions for a given aircraft until they actually were in an emergency under stress.