We all have that "sin that does so easily beset us". We all have that particular weakness. I have never been tempted to be an alcoholic (I don't like the taste of alcoholic beverages), but I am tempted just as much by other things. I have never been tempted to be addicted to drugs, but there are things I must constantly guard my heart against. Your besetting sin may not be mine, but I have one and it is just as dangerous to my soul as yours is to you! The importatnt thing is not to argue over who's sin is the greatest (some would say, "Well at least I'm not an alcoholic."), but to determine and deal with whatever our overwhelming temptation is! Sin is sin! Although the repercussions of one sin may be more readily visible or it may be deemed "more sinful" by human reasoning, all sin is cosmic treason against the ruler of the universe. I see a very overweight preacher on TV who preaches against the sin of adultery with all his might, forgetting that gluttony and addiction to food is sin as well.
The devil has watched us all our lives and he knows what temptation has worked against us time and time again. We pray and ask forgiveness and vow never to do it again and for awhile, we don't. But that temptaion doesn't go away, it hibernates. The devil puts it on the shelf for later. Just when we start thinking we have utterly overcome that temptaion and forget the Bible's warning that "when you think you are standing, take heed lest you fall" and "flee youthful lusts", we are overtaken once again by that same old sin! We can be overcomers, but only if we let Christ's strenth be our strength and obey His commands.
Some people start thinking that, because the temptation doesn't go away, maybe that's just the way they were born. They "weary in well-doing" and the devil tells them that the reason that thing keeps coming around is that, that is just who they are; that's just the way God made them! When they fall for that lie, they become what they think they are (as a man thinketh in his heart, so is he). It's easier to give in than to fight and believing the lie is easy when it comforts the flesh and makes a person feel like they're not resposible, God is.
Whatever your besetting sin is, take it to the Lord and ask for His strength in overcoming it. When you see it coming aroung the bend sometime later, stay away from it. Don't give it your attention for a second. Jesus will set us free from a thing, but the Bible says that whoever you choose to obey becomes your master. Don't give yourself back to it again but flee! And please don't ever entertain the lie that because you often tempted by that same thing, that God made you that way. God made you in His own image to be perfect as He is perfect!