You need to know where you are going. If not, you'll not even notice that you got there!
Having a destination is typical when setting out on a trip. Or at the least, having a general idea such as, "Let's go to the mountains and just look around." Knowing that destination makes it possible to prepare for the journey and to assess whether or not you are making progress in the right direction.
As sensible as that is, often, people have no idea where they are going with their lives. The live day-to-day unsure what it is they are trying to accomplish.
Having a life mission, a purpose for living, unveils the lanes in which you need to travel. Metaphorically.
For me, I like to say my mission two different ways. First, I say I am trying to create opportunities for people I encounter to become better versions of themselves. I say that differently, sometimes: Show the love of the creator to all creation.
Knowing what I am trying to accomplish lets me check what I'm doing to see if it fits.
(Caveat: rest and recreation.)
If you don't have a direction for your life, goals, and missions, then you might be wandering around in circles, never getting to anything significant.