As we live, things do not go as we planned. At some point in our life we hopefully realize this and stop planning at all, but we always can acknowledge that things will happen in a way which is completely unpredictable. Some of these things will make us happy, some will make us sad. This again is part of living.
When things do not go well, we always have lessons to learn. Maybe a lesson is obvious, maybe it takes some time to figure out, but these lessons are always there. So many of us do not forgive ourselves when things do not go right, especially when we miss out on something big. Instead, choose to acknowledge whatever happened as "in process" and take these lessons learned as a gift. These lessons make living life worth it, and a trip out of our comfort zone is always a gift.
Value lessons. Never be hard on yourself when things do not go as planned, instead know that there are great lessons to learn and move forward with grace.