Experience is a wonderful thing. Unfortunately we don't have any, so we have to learn from the experiences of others.
By far the most commonly mentioned example for us to learn from is the tragic fate of Air France flight 447, which crashed into the Atlantic Ocean with the loss of all aboard. This is used as an example in most of our lectures as aspects of meteorology, aerodynamics, instrumentation, systems, human factors and crew resource management all factored into the eventual outcome. Further information and the final crash report can be found at the links below:
In a more subject specific example of learning from others' experiences, stories from flying training were used in the recent Principles of Flight lectures on ground effect. This is where the wing becomes more 'efficient' once close to the ground, leading in broad terms to greater lift generation and less drag. Our lecturer's first anecdote was from his days as an E-3D AWACS pilot for the RAF; while being taught how to land his instructor left the power on as he flared (lifted the nose) for landing and the aircraft, instead of losing speed and sinking as might be expected, maintained height and speed and happily flew along the runway about 10ft up until a go around was initiated.
The second anecdote was about the issues associated with ground effect when taking off. A friend of his in basic flying training was going solo in a Jet Provost trainer that was heavier than usual, using a shorter runway than usual. When he saw that he wasn't going to take off successfully he rotated early in the hope of clawing his way into the air. The aircraft lifted in the ground effect at a speed well below the climb speed; the result was that when it left ground effect the drag increased and the lift reduced, so the aircraft slowed, stalled and crashed back into the ground. Just before impact the pilot ejected and had the story ended there, we might all just have taken it as an example of what can happen. The instructor's next words, however, really brought home the fact that flying, while much safer statistically than for example driving, is unforgiving of even relatively minor mistakes. The end result of the incident was "As he descended under his parachute he went through a wall and was stabbed to death as his knees went through his chest."
Stunned silence descended on the classroom. We've all had emphasised to us the Swiss cheese safety model, where holes in layers are blocked by other layers unless all the holes line up and an accident occurs, but for me certainly this really rammed home the first rule of aviation safety: check, check and then check again that everything is in order because if you don't, at some point you'll pay for it.