Empty Heads
You know how you always heard "idle hands are the devil's playground"? Well I think empty heads are the devil's playground too. We are wired to think, all the time, and to absorb whatever is happening around us. I think too many of us are not careful of what is going on around us, what is influencing us, what is filling our minds.
We are so influenced by the what other people are doing, and think that if we don't do those things we won't fit in. So we might drink too much, or look at porn, or be bored, or participate in activities that we know are not good for us, or any number of things that can separate us from the person we are meant to be.
I believe we all have a purpose. It is clear to some people, from an early age, what their purpose is, and sometimes I envy those people. Most of us can spend years floundering around trying to find what it is we are meant to be doing. Instinctively we know there is more to life than "work to home, home to work".
Realizing that purpose, knowing what it is, that is the difficult thing. An empty head allows all the wrong influences to bombard our minds and confuse the issue.
Your always going to be thinking about something, make sure you control what that is. Don't let your mind be idle and become a devil's playground. Read positive uplifting books, surround yourself with positive uplifting people, do positive uplifting things, like volunteering somewhere, go to a positive uplifting church, listen to positive uplifting music, fill your head with positive uplifting things and leave no room for the devil to squeeze in there and start to influence your thinking, causing you to be negative and unhappy.
You are more likely to discover your purpose with positive uplifting influences, because God in His infinite love for us, wants the best for us. We just have to create a fertile, cooperative environment for Him to work in. Get out of His way, and He will show you your purpose. Give Him the room in your head, not someone or something else.