Lessons in life are exercises for your soul.
When a lesson occurs, you are usually put in an uncomfortable situation. This requires your soul to step out in front of your character to overcome the lesson. When the lesson is complete, your soul steps back behind your character. If you pass the lesson, your soul becomes stronger. If you fail the lesson, it will repeat.
For example, Jacque is scared of spiders. She keeps being put in situations where she runs into spiders and gets upset. She even has nightmares about them. One day, when she finds a spider on the kitchen counter, she feels herself filled with a desire to get over the issue. Jacque, demonstrating uncharacteristic bravery, puts her hand out to the spider which gently walks on it. She then takes the spider outside and lets it walk off into the grass. After seeing that nothing bad happened, Jacque’s fear of spiders greatly diminishes.
After passing a lesson, it’s common to hear people say things like, “I don’t know where I got the strength to get through that!” Passing a lesson can be seen as obtaining a badge of honor. Some people get addicted to it and seek out lessons to conquer. Others may be afraid of lessons and choose to avoid them. This could make them reincarnate many times until they face their lessons and pass them.
When you pass a lesson, your soul no longer needs to experience the lesson as it already has the solution. As such, lessons are critical to the advancement of a soul.