If humans do not undergo trials, they will not experience great sufferings which are tribulations, which will later make them what they are. Trial and error is a method in which every last human being will experience faulty trials which are usually eliminated until the right method is found for a solution. When humans try most of the time, they don't know what the end results will be, but when they do, they implement them all and do it to the best of their abilities. To be fully successful in life, you must first experience failure. Life is full of daily obstacles and all humans have to go through trials to then endure everything they have experienced in their lives.