We can't change everything but that shouldn't get in the way of changing what we can,

Of all the possible outcomes in any situation only a few are probable and only one will actually happen.

Sometimes the outcome cannot be controlled like when a meteor falls on your head.

Sometimes the outcome can only be partially controlled like when two great teams meet in a championship.

Sometimes the outcome can be controlled by us to a very great exent like just about everything else that doesn't fall into one of the previous categories.

So don't spend time and energy on things you can't do anything about and don't let anything stop you from taking care of the things you can.