Never inflate your life jacket inside the aircraft so dont forget to take the instructions with you.
When the hijacked Ethiopian 767 crashed off the coast of Africa it became clear that a number of the passengers had...despite being told by the captain minutes before impact NOT to inflate their life jackets...done just that: inflated their life jackets inside the cabin.
The results were predictable, when the plane hit the water it filled so quickly passengers had to dive under water in order to get to the exits. Those who had not inflated their life jackets could hold their breath and dive for it. Those who had inflated their life jackets floated to the top of the cabin and were trapped against the ceiling.
Listen to the safety briefing, it might one day save your life.