No, not those kind of collisions.  ( That would take some serious sugar to make lemonade from that kind of collision! )  I'm grateful for the collision between my world and the world of others.  Like when my first world life collides with that of the third world life I have been honored to travel to.  The collision of those two worlds have literally changed my life.  I don't have the adequate words to describe my gratefulness for that collision.  Or the collision of God's grace with my weakness.  That has also been a life changing event.  What kind of collisions have happened in your life that you are grateful for?