I have to admit, being a relatively frequent flyer, although I stop reading or whatever I am doing, I will always try to listen to the safety brief, but invariably switch off and become a little complecant. I do however look at the card, and I also have a quick feel to see if there is a lifejacket still under my seat. I do know what to do, and how to open the doors etc if I needed to, and I listen attentively on new aircraft types or configerations. I also think others may pay more attention if they are sitting next to somebody who is at least looking in the direction of the cabin crew.
In addition, I do know some crew who have not briefed me on escape if I have had to sit in the flightdeck. If I am in an Airbus, I do not know how to get out as it is not my aircraft type, and I appreciate even though knowing how to use it, being told where the oxygen is and how to put it on.