To change a habit is hard but I must

That bad habit has followed me 21 years. It is destructive. I must change it.
I am aware of its difficulty but I have only one aim: change it at any cost, even death. Years of useless is less than a day of useful.
I must change my bad habit of useless thinking. It is hard but I will fight to change it and be angry each time it returns.
I could not give up on it.
I could not surrender.
To dream the impossible dream
To fight the unfightable foe.
To reach the unreachable star.