Although a goal is worth, some means taken to attain it may be not justifiable. Because any means involve reasonable means and unreasonable means. Unreasonable means which usually disobey rules of society and compromise others' interests even break law should not be considered because of harmful to society. 
First of all, moral conflicts may be sparked by inappropriate means in the process of reaching a goal. It is no wonder that there is a huge surplus of moral conflicts in the world, many of them involve scientific experiments. Embryonic stem cell presents a relevant case for analysis. Embryonic stem cell which is a kind of cell can solve many complex disease in the further. But opponent of Embryonic stem cell believe this kind of cell is actually one style of life and we can not save life through killing life. Because of this conflict between moral and science, the United States present a complex law to demonstrate that which experiment can be done and which can not. If scientists take a disputed experiments on Embryonic to attain a medicine goal, they may spark moral controversy even break the law. This is an excellent example of why people can not take any means to attain a goal.//第一个例子没有和论点（一些方式会引起道德冲突）有效的结合起来。
Secondly, other people's interests even life will be compromised by inappropriate means in the process of reaching a goal. A good example of this viewpoint involves many owners of coal mines in China. Workers in coal mines have a tough work environment with a small salary, their work is so dangerous that a lot of protection should be made to guard workers' lives. However, many coal mines do not have any protection for worker in oder to save cost. In fact, owners of coal mines get a large number of money. They cancel protections in coal mines for their self interest. Although owners of coal mines attain their goal to make a profit, their means endanger workers' lives even break the law. These illegal means should be forbidden to protect workers' lives. 
Another example of why some means are not justice involves milk. San Lu is a Chinese cooperation which produced dairy and milk. But this corporation filled some harmful materials in its product for a lower cost and a higher profits. Some children even lost their lives because of quality problems of San Lu's milk. Although San Lu reached their goal of a higher profit temporarily, its harmful means compromised other people's health and violated the relevant laws. These means should not be taken.
These are only two examples of why some means to attain a goal are not justifiable. Although we admire people who seek through various means to reach their goal, the precondition is that their used means should be reasonable.