You should never try to teach someone a big lesson without a chance for closure. Usually when we want to make a big effect we dramatize beyond our normal selves. This disorientates the person you are trying to teach and also tends to give a negative association with the experience. Unless the person desired to really learn something in the first place, this negative experience will leave a scarring effect and learning is sabotaged.
This is why it is good to find a good mentor or teacher when trying to learn difficult things by experience. The teacher can impart difficult lessons and still be there to pick you up when you feel like giving up. A passing stranger will make you feel you probably just have to avoid a certain situation.