You only need one awful experience to learn from it, this is something that I have been starting to understand as a human being and a psychology professional.
It turns out, going through one event can completely change the way you see the entire world for the rest of your life. I know a lot of us can understand this in regards to violence or painful traumas. However, it honestly takes much less than a massively shocking event to change your behavior forever. For instance, it only took my sister one long, bad day as a HVAC professional to forever change her routine. On one of her first afternoons after laboring as a professional HVAC worker for the local HVAC control dealership, my sister was sent to some harshly difficult heating and cooling system repair jobs. She was already distraught enough about demonstrating her recently earned heating and cooling certification for real residential HVAC customers and then the HVAC dispatcher sent her to the most difficult air conditioner and gas furnace repair jobs of the day. My sister got stuck at each HVAC appointment for various hours longer than she expected. The next thing she knew, she had been working a 12-hour day and her brain and body were in complete exhaustion mode. She was so tired when she left the last air conditioner repair that she nearly fell asleep behind the wheel of the HVAC truck. To this day, my sister is prepared for long, arduous HVAC repair services. She regularly keeps an extra bag of candy and a handful of caffeine pills in her heating and cooling repair truck.