Your reason why is your purpose. Have you discovered your purpose? And if so, are you trying to live out your purpose? We all have the same general purpose: to know God, to love God, and to serve God. However, we all have different specific purposes in how we are to know, love, and serve God. Our vocation has something to do with it, but it really stems from living out our general purpose in our uniqueness.
Everyone is a unique person. God loves us all in our uniqueness. Yes, as a group, but also as an individual. And our uniqueness provides us with a way to know, love, and serve God that no one else can fulfill. No one can love God like you can, because only you can be you. I cannot love God for you. I can love God myself, but that can never replace or make up for you loving God like only you can.
We cannot love a God that we do not know. And we will not serve a God that we do not love. So, we must begin our reason why by beginning to know God. God is infinite, so there is no way we can know God fully. But we were created to know God, so there is reason for us to desire to know God. And once we begin to know God, we fall in love with God. A God willing to stoop to becoming human just to save us from the eternal punishment of our sins is easy to fall in love with. And if we love God, we will want to serve the God that serves us. “[T]he Son of Man did not come to be served but to serve and to give his life as a ransom for many.” – [Mark 10:45]
Many never look to their reason why during this life. They look to the world to see their purpose. But if God exists, and He does, then our purpose is for greater things than this temporal world.
Jesus, You came to reveal the love of God to mankind. Help us to return love to You in humble service and always seek to know You more. Amen.