There are no mistakes in life, only lessons. There is no such thing as a negative experience, only opportunities to grow, learn and advance along the road of self mastery. From struggle comes strength. Even pain can be a wonderful teacher.
We might not be able to control the weather or the traffic or the moods of all those around us. But, we most certainly can control our attitude towards these events. We all have the power to determine what we will think about in any given moment. This ability is part of what makes us human.