My standard procedure when sitting down is to check life vest (I've never had a missing one in nearly 200 segments) and have a row count to the nearest exit. I have no fears about flying but think being at least remotely prepared is worthwhile, that along with paying attention to the safety briefings.

Story familiar to many I think, last flight back from Tel Aviv there was a woman sat next to me who kept her headphones in, on a phone conversation, during the safety briefing. Crew asked her to hang up, turn the phone off, and listen to the briefing. She replied she flys every week and knows what to do, the cabin crew asked her "where is the nearest door and how do you open it". A rather embarrassed passenger removed her headphones. She was a special one, claiming to "forget" to tell the crew she has a severe nut allergy about 2 hours into the flight and then having a tantrum about them serving peanuts