defining "defining moments "

I am a strong believer in defining moments.now i dont know the significance of a defining moment or the deeper meaning behind it but i believe that defining moments happen.
To me a defining moment is one which you wont ever forget. Its something that will shape you as a person and will shape the way you lead your life. It may have a small affect (so much so that you dont recognise it) or it may have a powerful affect. A defining moment can occur when you meet someone for the very first time... When you say goodbye to someone.... when you figure something out.. when you see something special... when you feel something special... It could be anything.
Maybe at first you dont recognise your defining moments. Maybe one day you look back and you can see all the moments that you still remember (when you're 85 or something) and realise that they defined you.