I can fill up a book with analogies and metaphors regarding life and how we cannot foretell what will happen in the future. I won't bore you. Here is the short version:
a. we cannot tell the future
b. we need to cross bridges on our life's journey
c. if you burn them you will not be able to go back, some times not even forward.
d. bridges=people, opportunities, relationships, jobs
Think about what that means. It is better to have options and easy ways to walk over rivers. Life is difficult. There is no need for you to make it any harder by burning your bridges.