Thorn in the Flesh

As a growing Christian, I have a lot of questions i need answers to. I hope that answers to these questions will not only add to my knowledge but will also add your own.

In 2 Corinthians 12:7-10 (New King James Version) Paul talks about the thorn in his flesh which God did not take away from him. Ever since i read this passage, my mind has been bugged down with questions.
What does this thorn in the flesh represent? What does it mean? Sickness, challenges we go through etc.?
Are there things we desire that God will not give us? e.g. healing? children? spouse? break-thru? good career? success?

(NKJV) 7 And lest I should be exalted above measure by the abundance of the revelations, a thorn in the flesh was given to me, a messenger of Satan to buffet me, lest I be exalted above measure. 8 Concerning this thing I pleaded with the Lord three times that it might depart from me. 9 And He said to me, “My grace is sufficient for you, for My strength is made perfect in weakness.” Therefore most gladly I will rather boast in my infirmities, that the power of Christ may rest upon me. 10 Therefore I take pleasure in infirmities, in reproaches, in needs, in persecutions, in distresses, for Christ’s sake. For when I am weak, then I am strong.

(New Living Translation) 7 even though I have received such wonderful revelations from God. So to keep me from becoming proud, I was given a thorn in my flesh, a messenger from Satan to torment me and keep me from becoming proud. 8 Three different times I begged the Lord to take it away. 9 Each time he said, “My grace is all you need. My power works best in weakness.” So now I am glad to boast about my weaknesses, so that the power of Christ can work through me. 10 That’s why I take pleasure in my weaknesses, and in the insults, hardships, persecutions, and troubles that I suffer for Christ. For when I am weak, then I am strong.

Buffet means:
To hit or beat, especially repeatedly.
To strike against forcefully; batter: winds that buffeted the tent.
To drive or force with or as if with repeated blows: was buffeted about from job to job by the vagaries of the economy.
To force (one's way) with difficulty.

Does God leave us with thorns in our flesh to torment us so that we do not become proud and forsake him? Cos we all know that when things are going good, it's human nature to forget God and only return to him in times of struggle. It is human nature for the rich and successful to think there is no God and even if they do believe, they think it's their own doing that got them to where they are.